Investigation
of Drowning Accidents
Section editor: Jerome Modell
12.1
Introduction and Overview 619 Jerome Modell
12.2
Behaviour of Dead Bodies in Water 620 Jaap Molenaar
12.3
Search and Recovery in Near-Shore Waters 622 James Howe
12.4
Search Techniques 625 12.4.1
Search Techniques for Dead Bodies:
Searching with Dogs 625 Adee Schoon
12.4.2
Search Techniques for Drowning Victims:
Recovery Using Side Scan Sonars 627 Robert Williamson
12.4.3
Infrared Detection Systems
for Maritime Search and Rescue Units 630 Germ Martini
12.5
Homicidal Drowning 633
Andrea Zaferes and Walt Hendrick 12.6
The Approach of the Pathologist to the Diagnosis of Drowning 636 Ian Calder
Peter Cornall, Roger Bibbings and Peter MacGregor 12.8
Legal Aspects and Litigation in Aquatic Lifesaving 645 Jerome Modell
12.9
Legal Claims in Drowning Cases 647 Rutger Schimmelpenninck
12.10
The M/S Estonia Disaster and the Treatment of Human Remains 650 Eke Boesten
12.11
Maritime Accident Investigations 653 John Stoop
Editor
▬ Jerome Modell
Authors
▬ Roger Bibbings
▬ Eke Boesten
▬ Ian Calder
▬ Peter Cornall
▬ Walt Hendrick
▬ James Howe
▬ Peter MacGregor
▬ Germ Martini
▬ Jerome Modell
▬ Rutger Schimmelpenninck
▬ Adee Schoon
▬ John Stoop
▬ Robert Williamson
▬ Andrea Zaferes
Editing Assistant to Jerome Modell
▬ Anita Yeager
12.1
Introduction and Overview
Jerome Modell
This section contains several chapters dealing with state-of-the-art techniques for identification and retrieval of drowning victims, accident investigation and legal recourse when injury is sustained either by the victim or the rescuer. These issues initially had not been considered as a potential topic for the project and for this reason no task force was established and no recommendations were made during the World Congress on Drowning. However, in the final program a large body of knowledge and several discussions on the investigation of drownings and retrieval of drowning victims were included. Therefore, it was felt important to the coordinating editor to include a section in this Handbook on Drowning.
Inherent in the discussion of these items is that social expectations and cul- ture play a large role in determining the importance and finances allocated to investigate these accidents and to recover the deceased. It is, perhaps, ironic that, in many locales, it appears that society is willing to invest larger sums of money
to retrieve dead victims than it is to ensure the proper elements are in place pro- spectively to promote water safety and effective rescue.
My intent is not to belittle the importance placed on retrieval of drowning victims but, rather, to point out that while society seems to be willing to retrieve a dead body at any price, it is not always willing to provide adequate finances and personnel necessary to avoid such catastrophes. I would advocate that pre- vention of fatal and near-fatal aquatic accidents is far more cost effective than retrieval efforts after the fact.
Furthermore, emphasis should be on learning from each drowning episode as to what could have been done proactively to prevent it. To experience a drown- ing in an environment that is unsafe or takes unnecessary chances, is tragic. But, to permit such conditions to persist, thereby inviting further drownings, to me, is incomprehensible.
Several of the chapters in this section deal with the methodology of finding dead bodies. I certainly hope that this methodology will also be expanded to identify the hazards that may have contributed to the drowning episode in order that they can be modified or eliminated completely. Investigations of accidents in maritime events should not be focused merely to assign blame for the disaster at hand but, rather, to recommend improvements in safety so as to avoid such disasters in the future.
Chapter 12.9 on legal claims in drowning cases is particularly fascinating to me because it almost assumes that in any drowning episode, someone should be compensated financially for injury or loss. This merely is a testimony to our litigious society whereby one person’s unfortunate disaster results in another person’s financial gain. I have a difficult time dealing with that concept and be- lieve that one should attempt to rescue a drowning victim because it is the right thing to do, not because one may be sued if they do not act as a lifesaver, or they may sue the drowning victim himself/herself if they, as the voluntary rescuer, suffer any injury.
Obviously, a great deal still needs to be done in regard to investigation of aquatic accidents in order to determine their cause and to institute preventive measures to decrease their incidence. It is only through such investigations that we will continue to make the water a safer environment for recreation and busi- ness.
12.2
Behaviour of Dead Bodies in Water
Jaap Molenaar
Knowing the behaviour of dead bodies in water is very important for rescue services. This knowledge facilitates completion of the search operation. Effec- tive procedures may result in a timely, successful rescue within a time frame that resuscitation can potentially still be useful. In other situations the recovery of a body can be done quickly and the operation can be limited in size and dura-
tion. A limited period also minimises the length of the emotional and uncertain period of the family and beloved ones of the missing person.
Worldwide there is very little adequate research data or knowledge available in this field that allow a systematic, fast and effective search procedure. Data usually reflect gathered incident information, which is often incomplete and has not been subjected to scientific analysis.
The behaviour of dead bodies in water depends largely on the type of water in which the incident has taken place. If we focus on the types of water, the fol- lowing two categories emerge:
▬ Still water, such as canals and lakes
▬ Current water (or flowing water)
▬ Slow current water
▬ Medium current water
▬ Fast current water
▬ Seasonal current water, which can change in appearance. Medium speed current water becomes fast current due to water from melting ice in the spring or heavy rainfall, or into slow current in the summer due to a dry period.
12.2.1 Still Water
Frequently the location where the body has submerged is the location where it will be found afterwards. A possible influence on the behaviour is the system of refreshing or flushing of a canal or lake. If the body enters the water close to an entry point of fresh water, the movement of the water at the intake can influence the behaviour of the body by the turbulence in the water. Similar results can be found for exit points by the use of locks.
If sufficient vessels sail through still water and the body is in balance with the water, the power of propellers can move the body to another location. This only happens, however, when the bottom of the canal or lake is flat, hard, with- out obstacles and the water is relatively shallow. Another potential influence is the difference in the temperature of the water layers. It has been postulated that the body hovers through the water on these layers as the water increases in mass when it is colder. However, this concept remains to be proven.
12.2.2
Current Water
There is a diversity in current water caused by:
▬ The difference in height between two points
▬ The amount of water that is transported per unit of time
The velocity and intensity of the current is of great influence on the possible behaviour of dead bodies in water. Other aspects that can be important are the
bottom contour and the bottom type. The bottom contour depends on the pres- ence of obstacles on the water bed, such as large stones or rocks, steel cables and other objects. The bottom type is what the water bed is made up of, such as mud, sand or solid.
The most common cases reported in current water are:
▬ The dead body was found where the submersion occurred
▬ The dead body was found 300−500 meters downstream
▬ After several months the dead body was found at a long distance (as far as 160 kilometres) from the location of submersion
▬ The dead body was found across a river or between two breakwaters in a river.
Variation in the velocity of the current has an influence on behaviour. For exam- ple, a river that normally has a velocity between 0.5 and 1 metre per second can at some times have a velocity of 4 or 5 metres per second. Such a difference can have a substantial influence on the behaviour of a dead body in this water.
In 1999 the Council of Regional Chief Fire Officers in the Netherlands launched a research program to gain more knowledge about the behaviour of dead bodies in different types of water. The first step of this research program was to gather information. All fire brigades with a rescue diving team were asked to complete a questionnaire after the recovery of every dead body. In the past few years, questionnaires have been received but often the information was not com- plete. Often the location or time of submersion was unknown. Thus it is not pos- sible to draw scientifically valid conclusions based on the information received.
The research program will continue until at least 100 cases with complete and useable questionnaires are received. Those cases will then be analysed accord- ing to scientific methods. The hypothesis of the research program is that there is a relationship between the location of submersion, the velocity of the water and the expected location where the body is found. Based on this study, search attempts may become faster and more effective. However, the results could also show that there is no relation at all and every prediction is based purely on spec- ulation. Material from other research programs from around the world will be used for reference and comparison in the analysis phase of the report.
12.3
Search and Recovery in Near-Shore Waters
James Howe
Search and recovery efforts for missing persons conducted in near-shore waters are those conducted in waters no more than 1 mile from a shoreline. Near-shore waters might also be accurately called the recreation zone because most ocean recreation activities are undertaken in this area. Nearly all recreational surf ar- eas are found here.
The environment of near-shore water is very hydrodynamic. This is where streams, rivers, and storm water drainage channels run-off into the ocean. It
is typical to find permanent, recurrent, and temporary water currents (rip cur- rents, long shore currents) in these areas. The presence of currents generated by either wave action or run-off causes bottom scouring. Bottom scouring in turn affects the intensity, location, and direction of the water currents and negatively affects water clarity.
Near-shore waters are the home to a thriving eco-system. This well-devel- oped eco-system includes a wide array of marine organisms. As in any fully developed eco-system, there are multiple levels of predation and many of the organisms have developed powerful defense mechanisms.
Shoreline topography and geology have both direct and indirect effects on the near-shore waters they abut. Ease of access to the shoreline is a major deter- mining factor in the level of water use for recreational activity. Shoreline com- position (sand, pebbles, boulders, coral) is a factor in the ocean skill level of persons accessing the waters. The more foot friendly the beach, the lower the ocean skill level of persons going into the water.
Near-shore waters are where the vast majority of ocean sport participants are found. Activities include swimming, snorkelling, diving (into the water), surf sports (body surfing, surfing, body boarding), wind sports (wind surfing, kite surfing, small sailboats), and small scale harvesting of shells, seaweed, fish, and other animate and inanimate objects. Near-shore waters are, in effect, a highly dynamic wilderness area where the vast majority of ocean recreation activity happens. The implications for search and recovery professionals are evident.
Successful search and recovery efforts in all wilderness environments have common elements. The first is a strong base of local knowledge of the area. This includes the terrain, common hazards, unusual hazards, weather impacts, ani- mal life and behaviours, common entry and exit points, shelter areas, common activities and, recollection of past search efforts and the results. It is not always the rescue professional who will have the most extensive local knowledge of the search area. In most cases, local fishermen, surfers, divers, and community resi- dents should be included in the pre-planning, execution and de-briefing phases of search and recovery efforts.
Initial information regarding a missing person, or persons, is often not com- plete or totally factual. It is important to qualify witnesses as to their level of local knowledge to determine the type and extent of search effort to undertake.
It is common that visitors to near-shore water areas may confuse the behaviour of some marine life with that of a person in distress. There are also many other circumstances in which the initial report may need to be qualified prior to a search effort being undertaken, especially when children or young adults are reported missing. Information regarding the location, activity, experience level, and emotional and physical health of the missing person should continue even after a search is initiated to help define the search area.
A second common element required for all effective searches is a coordinated communications system. Near-shore searches present special challenges. In de- signing a communications plan for water searches the first priority is to establish a link from the water search site to shoreline assets. Sea-to-shore communica- tions can be established by either visual signal or radio communication. The use of radio communications normally requires the use of a boat, personal water-
craft, or aircraft. In-water communications are essential to ensure rescuer safety and to coordinate the search effort. In-water communications are best accom- plished by use of the buddy system. In this system, teams of two or more search- ers are designated and assigned search areas. Each team member is required to keep visual contact with all other team members at all times. Each team must check in with the surface search coordinator to report findings and receive new search assignments. This system allows for specialised search teams (surface swimmers, craft assisted snorkel divers, SCUBA equipped bottom searchers) to be used in a coordinated effort.
A third common element is command and control protocols for the search effort. A basic incident command model is recommended to effectively manage this aspect of the effort. This emergency management system, widely used in the US, designates roles and responsibilities for everyone involved in the search and recovery effort.
An often overlooked aspect of search and recovery efforts are the needs of family members or associates of the missing person. It is important to address their needs during the search effort. This could include access to information and personal communications; counselling or faith-based services; and basics such as food, shelter, clothing and transportation. Media inquiries and access to the search area must also be managed. The incident command model designates a role for media management and public information dissemination.
The specialised work of near-shore search and body recovery begins with training the rescuer. All rescuers who work in this highly dynamic environment need extensive hands-on training, on a continuing basis, to be effective. It is the basic ocean skills of swimming, surfing, and diving underwater that form the basis of competence for these men and women. Mechanical devices or techno- logical solutions are not a substitute for these skills.
Specialised mechanical devices can, however, greatly enhance the abilities of near-shore rescuers. SCUBA apparatus allows rescuers to access deep-water areas with greater speed and efficiency, and for longer periods. Rescue craft give rescuers speed and area coverage advantages. They also provide rest and recov- ery platforms. Aircraft and helicopters provide excellent area coverage. They also allow searchers excellent water and bottom surveillance if water clarity is good.
Technology also provides professional rescuers with additional tools to as- sist in the search. Depth finders and fish finders can assist in locating specific bottom structures. Global positioning systems (GPS) help in determining and maintaining search grid areas. Infrared light may be of assistance in certain low- light situations. There are some indications that thermal imaging technology will prove to be beneficial in locating bodies underwater.
The search for missing persons in near shore waters continues to be a skill- intensive and dangerous activity. The most prudent investment professional res- cue organisations can make is in the training of their personnel in basic ocean skills, physical fitness, and local knowledge of their near-shore areas. Risks to rescue personnel can be minimised and mission success maximised by using the aforementioned systems, equipment, and technologies.
12.3.1 Website
▬ http://training.fema.gov/EMIWeb/IS/is195.asp
12.4
Search Techniques
12.4.1
Search Techniques for Dead Bodies:
Searching with Dogs
Adee Schoon
In general, police dogs are associated with well-trained attack dogs. These dogs are trained to obey their handlers under all circumstances and are faithful partners during patrol duty. However, there is also a less well-known type of police dog, the search and detection dogs. These dogs are trained to detect cer- tain odours, and to respond to them in such a way that their handlers realise it has discovered an odour source. This is done through what is known in animal learning behaviour as instrumental learning: specific odours lead to a response, which in turn leads to a play reward. To the dog it is a game, to the police it is a useful detection tool.
Search and detection dogs have been in use by the police for almost a century, and have been used to detect many substances. Today, they are trained to de- tect narcotics, explosives, tobacco, accelerants, human scent, and dead bodies.
There are two important aspects to their training. The first relates to the odours the dogs are trained on. This needs to be varied: the full range of products that the dog needs to respond to, as well as significant differences in concentration.
The second aspect concerns the searching itself. The dog must learn to locate the odour source precisely and to search under all circumstances, ignoring dis- tractions. Two different kinds of search and detection dogs can be used when searching for victims of drowning: human scent tracking dogs and dead body detection dogs. In the Netherlands, the National Police Agency coordinates the deployment of these dogs.
12.4.1.1
Training Search Dogs
The human scent tracking dog is trained to follow human scent on a trail, to find human scent on small and large objects that have been touched, and to find peo- ple themselves. They are taught to do so in- and outside of buildings, in urban and industrial areas, in rural areas, woods, heath, and in and on water. Dead body detection dogs are taught to detect human blood remains and corpse odour in different stages of decomposition. They are taught to search in the same areas as the human scent-tracking dog.
For the water training, some special techniques are used. The odour sources used to train the human scent tracking dogs are worn clothes and hair. Dead body detection dogs are trained on last-worn clothes from the deceased people.
The dogs are taught to search from the waterside and from a boat. The handler and the dog start downwind, and work their way towards the source. From the banks, this is relatively straightforward. In a boat, the dog sits on an elevation in the bow, allowing it to hang over the side and smell the water surface. The handler watches his dog and directs the helmsman. The boat is steered in a zig- zag pattern, starting downwind and gradually moving upwind. To pinpoint the odour source more precisely, the dog is then worked in the reverse direction.
The handler has to learn to ‘read’ his dog, especially when in the boat, where the dog catches a whiff but cannot move independently towards the odour source, the handler has to watch his dog closely and instruct the helmsman towards the source.
12.4.1.2
Deploying Search Dogs
Whether to use a human scent tracking dog or a dead body detection dog de- pends on the duration that a person has been missing. Depending on a number of factors, amongst others the temperature, it takes some time before the typi- cal corpse odour is emitted. So, human scent tracking dogs need to be called in after a recent disappearance, and dead body detection dogs if a person has been missing a long time.
It is relatively easy to get the dogs to make a reliable response. It is much more difficult to then locate the body. The volatile molecules move away from an odour source in a plume: narrow at the source, and widening as the molecules float away in the air current. Independently moving dogs will zoom in on such an odour plume, detecting its boundaries and keeping within the plume moving towards higher concentrations until they reach the source. However, when such an odour source is located under water, the movement of the volatile molecules is influenced by both water and wind movements. If the direction of the current is in line with the wind direction, the dog can alert to the odour hundreds of meters away from the source depending on the strength of the wind and water currents. However, if the direction of the current is opposite to the wind direc- tion, the dog will alert much closer to the source, or even upwind depending on the relative forces of water and wind movement. Add to this the circular water movements caused by cribs in rivers, undercurrents and other curious water and wind movements, and the complicated relationship between the place where the dogs alert and the position of the dead body becomes clear. On top of this, divers who have to go under water for the actual search have very poor vision in murky waters and often have difficulty in finding the body, even in stagnant water, sometimes even when at less than arm’s-reach distance.
In spite of these difficulties search and detection dogs prove to be valuable in searching for dead people. In a case where the victim was in relatively stagnant water, the dead body dogs indicated a spot near a bridge after a one-hour search.
The day before, several policemen had searched the area from a boat, and on
the day the dogs were deployed 20 people and a helicopter were also searching.
Following the indication from the dogs, four diving teams searched the area and located the body after 3.5 hours at the spot the dogs had indicated. In a second case in a canal, a person had gone missing one night. Human scent tracking dogs were called in the next day and indicated a spot after searching the area for 1 hour. The area was searched by divers for 5 hours and by using a tow net for an additional 8 hours without result. Almost a month later, dead body detection dogs searched the area and located a spot some 50 meters south of the initial area after a 3-hour search. Again, divers searched the area for 4 hours without result.
Two weeks later, the dead body dogs were called in again. While coasting the canal north of the area indicated before, the handlers saw the dead body floating in the water. This was some 500−600 metres north of the earlier indication areas, and the body was still floating with the current further north quite rapidly. This was remarkable, because the general water movement in the canal is south, and the earlier searches had been conducted on these premises.
12.4.2
Search Techniques for Drowning Victims:
Recovery Using Side Scan Sonars
Robert Williamson
Recent technology improvements in side scan sonar have provided the search and rescue community with a relativity new search tool for identifying the loca- tion of drowning victims and thereby facilitating their recovery. When deployed and used properly, the side scan sonar allows a systematic and thorough search of an area by creating real time sonar images of the water bottom and a drown- ing victim. Only when the victim has been located or a suspect target identified is it necessary to deploy divers. Side scan sonar is the tool for conducting the search while divers are used for the recovery. The information contained in this chapter is provided to assist teams, which have already been trained on their specific equipment.
12.4.2.1
Establishing a Search Area
The establishment of a drowning victim side scan sonar search area is based on information gained from talking to eyewitnesses or locals familiar with the body of water to be searched. Information regarding the water entry of the vic- tim and area where last seen can establish a starting point for the search. If no entry point can be established but an empty boat was located, then the wind and water current effects on the boat would be critical in establishing a search area.
Once this basic information is known the four corners of the search area should be marked on the navigation plotter of the system. Navigation waypoints should then be entered to delineate the track lines that will be used to conduct the search.
These track lines should be established to allow for a minimum of 10% overlap
of the swath lines, which will be created by the sonar scanning range selected.
The search swath, if using both sides of the towfish, will be double the scanning range selected. For example, if a range of 40 meters is selected for the search then the swath coverage will be a total of 80 meters. By overlapping the swath lines by 10%, 100% bottom coverage is guaranteed.
When conducting sonar operations, information regarding water depth, bot- tom contour and type should be taken into account in establishing track lines.
Track lines should be established to run parallel contours of equal depth to allow the towfish to be run at a consistent depth. If the track lines are perpendicular to contour lines then additional work will be required to constantly adjust the altitude of the towfish so it remains the correct distance off the bottom. If dur- ing the search the victim is not located and bottom conditions created extensive shadows that would hide a victim, then it will be necessary to establish track lines that run 90º to the original track lines. This provides visibility to areas that were hidden by shadows during the initial search.
12.4.2.2
Determining Scanning Ranges
Victim searches are best conducted on a 50-meter or less scanning range scale.
The bottom conditions will in part dictate the maximum range on which a suc- cessful search can be conducted. If the bottom is flat and featureless, then a max- imum scanning range of 50 meters can be used. The victim will appear small on the screen using this range but with the shadow cast by the body, it should still be recognisable. The 50-meter scanning range is normally the longest range that can be used to allow for recognition of a human body.
If the bottom is littered with rocks and debris then the scanning range should be reduced to a range that will allow the operator to distinguish between bot- tom objects and the victim. In some situations, especially with trees either still standing or lying on the bottom, locating and identifying a victim can be dif- ficult. When searching in debris littered waters it may be necessary to mark sus- pect targets and then have a diver ground truth the target to either verify or discount that the target is the drowning victim.
There are trade-offs when selecting a scanning range. Longer scanning rang- es (40−50 meters) allow for a shorter search period but a drowning victim will present as a smaller target on the screen and will possibly be missed. Searches using a smaller scanning range (10−20 meters) will present the victim as larger on the screen making it easier to identify but requires a longer search time. If the area to be searched is large and the bottom conditions will allow, it is advised to search on a scanning range of 40−50 meters and mark all suspect targets so that if the victim is not positively identified, then the marked suspect targets can be re-scanned at a shorter range.
12.4.2.3
Setting Towfish Scanning Altitudes
A proper towfish scanning altitude is based on the sonar scanning range select- ed for the search. A minimum altitude is necessary to allow the sound to reach out to the scanning range selected. A maximum altitude is one that will allow imaging of the bottom while at the same time providing clearance for the tow- fish from obstacles. Normally, the towfish is flown above the bottom 10%−20%
of the scanning range. If the scanning range selected is 50 meters, then the tow- fish should be flown 5−10 meters off the bottom. When the bottom conditions are unknown, the initial search should be flown at 20% or 30% of the scanning range in an effort to avoid the towfish striking or snagging debris. Once the bottom conditions become known, the towfish should be flown at 10% of the scanning range for the best possible images. When scanning at higher towfish altitudes the range delay feature of the system can be employed to reduce the amount of water column displayed on the screen and increase the amount of bottom displayed. The higher the towfish is flown off the bottom, the smaller the shadow cast by the victim. Conversely, the closer to the bottom the towfish is flown the larger the shadow cast by the victim.
12.4.2.4
Drowning Victim Recovery
Once the image of a drowning victim is identified it should be marked on the plotter so that a recovery can be made. Several techniques can be used to re- duce a divers exposure to depths and challenging water conditions. With most side scan sonar systems the global positioning system (GPS) is used to provide the system with speed and location information. With some systems the image is geo-referenced allowing the operator to select the victim in the image and to know the latitude and longitude position. If proper system layback has been entered and if differential GPS positioning is available, the latitude and longi- tude location of the victim could be within a 3 to 5-meter radius of accuracy. In shallow water a weighted marker could be placed over the victims latitude and longitude position and a diver could conduct a circle search of the area using the marker as a reference point.
Another method that can be used for shallow water dives, but is more useful for deeper dives where diver bottom time is limited, is a marker target. Con- structing a 3‘×3’×3’ cage using copper tubing for the frame, covered with chick- en wire, and with no plastic covering on the wire, and lined with thin sheets of Styrofoam, makes an easily identifiable marker target. This target would be weighted and attached to a polypropylene line. The line would run to a buoy and sheave at the surface. The line would pass through the sheave and be terminated with a small weight. This will allow the buoy to be positioned directly over the target at all times. The target would be placed in the water based on the lati- tude and longitude position of the victim. Both the target and victim would be scanned and then the target would be moved closer to the victim. This scanning and moving would be conducted until the target was relatively close to the vic-
tim. A distance and heading from the target to the victim could be provided to the diver after marking both the target and victim on the plotter. Upon descent of the diver he would use this information to establish a limited search pattern to recover the victim. On one documented recovery the marker cage was posi- tioned directly over the victim allowing the diver to make his descent, remove the cage and complete the recovery.
12.4.3
Infrared Detection Systems for Maritime Search and Rescue Units
Germ Martini
In the night of 27 July 1999 a fatal accident occurred when a small boat in the shallow waters of the Waddenzee, the Netherlands, could not be found in time in spite of extensive search and rescue (SAR) operations by lifeboats and heli- copters. In their conclusions of the investigation of the tragedy, the Shipping Chamber of the Dutch Council for the Transportation Safety, recommended the introduction of thermal imagers as a resource for maritime and air-borne units engaged in SAR operations. This chapter overviews the operational aspects of infrared detection systems in SAR operations.
12.4.3.1
Infrared Detection Systems
An infrared detection system is a thermal imaging system integrated in an in- frared video camera. The system measures the thermal energy of an object in relation to background energy of the environment. The camera generates a real- time video signal that allows an operator to view all movements of a thermal picture on the scene. Infrared cameras can provide continuous day and night visual surveillance.
All natural and manmade objects emit infrared energy. The ability to distin- guish and to register on-line subtle temperature differences adds a whole new dimension to sight and reveals what was once thought to be invisible.
12.4.3.2
Practical Use of Infrared Detection Systems
The development of infrared cameras was initiated in response to the military demand for night vision systems based on infrared thermal imaging. Since then, thermal imagers have become accepted internationally as a vital piece of equip- ment for the army, firefighters and police. Thermal imaging devices decrease search and rescue times in buildings filled with smoke. Infrared detection sys- tems have proven their effectiveness in the war on drugs and crime, in traffic investigations and surveillance.
Infrared detection systems are also employed to check clothes, boots and tents for heat loss in below zero temperatures. Other infrared detection systems
are used by companies engaged in process control, predictive maintenance and automotive, electrical and mechanical applications.
The past 4 years have seen an explosion in activity in companies manufac- turing thermal imagers to the point where the choice is now both extensive and confusing.
12.4.3.3
Marine Applications of Infrared Detection Systems
There are marine applications using infrared detector systems for SAR opera- tions to detect unlit buoys, small vessels, and other hazards to navigation. Of- ten the systems are used to complement radar by viewing selected objects in real-time video. Infrared detection systems are used for marine law enforcement such as to detect if a vessel has been operated recently and if asylum seekers are thought to be in hiding.
Based on available information on infrared cameras, requirements for the use of infrared detection systems by the Royal Netherland Sea Rescue Institute for maritime SAR operations have been identified (⊡ Table 12.1).
⊡ Table 12.1. Requirements for use of infrared detection systems for maritime SAR operations
– Simple and fully automatic to operate, leaving the crew free to concentrate on SAR activities
– Resistant to spray, water, short-term immersion in water, cold, heat, shocks and vibra- tions produced by lifeboats
– Short warm-up time to thermal image
– Long battery life and rechargeable battery packs – A video signal for connection to a compatible monitor – A full colour camera and monitor
– The choice between a black or a white background, if the monitor is displaying in black-and-white
– Unaffected by rapidly changing light levels or by the level of ambient light – Camera with folding-screen
– If mounted, a camera with pan/tilt can achieve 360º continuous pan – Anti-ice feature and wiper to avoid freezing at low outdoor temperatures – Training
– Technical support and repair service
Current experiences on board KNRM lifeboats show a large detection range of humans between 50 and 1800 meters in an open and calm sea. A limitation with infrared detection systems, however, is that they are not always water or spray proof and not weather proof in adverse weather conditions. Also, the in- frared detection systems do not detect persons drifting in open seas as easily as radar systems.
Based on the current set of experiences, the KNRM is considering a number of options for the future use of infrared detection systems:
▬ To equip all 30 larger lifeboats with a mounted infrared camera allowing the operator to view a thermal picture of the scene on a monitor in the wheel- house
▬ To equip all 30 smaller lifeboats with a handheld infrared camera
▬ To equip all 20 KNRM trucks with a mounted or a handheld infrared cam- era
It has already been decided that it would be extremely expensive to provide in- frared detection systems on board all KNRM lifeboats and trucks. Therefore, lo- cating infrared handheld cameras at centrally chosen places in the Netherlands is being considered. When the need for an infrared system arises, the camera would be supplied on location to be used by a lifeboat or a helicopter. Another option is to provide only some lifeboat stations permanently with infrared hand- held cameras.
To identify the best solution, two lifeboat stations will be equipped with a handheld infrared camera (⊡ Fig. 12.1). This will allow the acquisition of first- hand experience, practice and the collection of data and information from the crew members for review later. One element of the evaluation will be to observe whether the essential basic skills of the crew members of lifeboats are not com- promised by the use of modern technology. Also, the effect of the introduction of infrared systems on the use of ‘bridge resource management’ principles during both exercises and SAR operations (⊡ Fig. 12.2) will be observed.
⊡ Fig. 12.1. Handheld camera
12.5
Homicidal Drowning
Andrea Zaferes and Walt Hendrick
▬ An adolescent drowns in a lake where he frequently swam, and it is ruled accidental. Twenty years later his brother confesses that he and his friends watched a man drown the teenager.
▬ A woman is found drowned in a bathtub. The ruling is accidental drowning.
When the husband of the woman drowns his second wife, the truth is discov- ered. Both were murders.
▬ An investigation for possible foul play ensues when a non-swimmer, college student is reported missing. When he is found submerged off a friend‘s dock, the investigation immediately ceases. Accidental drowning is ruled. Later foul play was detected.
The initial determinations of these actual drowning incidents as accidents are not uncommon. What is uncommon is the discovery of their red flags and the ensuing investigations. This chapter intends to contribute to a general awareness that many homicidal drowning cases are being missed.
12.5.1
Drowning Investigations
As many as 20% of child drowning incidents may be homicides. Notably, drown- ing in females may be a red flag for foul play in illogical child and adult drown- ing. A large percentage of these homicidal drowning incidents are either not sufficiently investigated or are not investigated at all. There are several reasons for this. “Tragic accident” is often a mindset that causes tunnel vision. The red
⊡ Fig. 12.2. Infrared picture of a ship
flags normally found on homicide victims or at the scenes are rarely present, and law enforcement and medical personnel are not trained to recognise the red flags specific to homicidal drowning. The body may not have been recov- ered. Rescue personnel may inadvertently destroy evidence. Because drowning evidence is usually circumstantial rather than hard, cases are difficult to in- vestigate and prosecute. Hence drowning cases may be pushed back when case loads are heavy. The drowning determination by process of exclusion can make it difficult to prove whether a victim drowned or was disposed of in the water.
Witnesses are often grieving family members, which adds to the ‘tragic acci- dent’ mindset. And very importantly, if a drowning is investigated, it is usually motivated by hindsight, after valuable scene evidence has been lost. Therefore a standard information gathering incident form to use on every drowning inci- dent would be very helpful.
12.5.2
Land and Water Deaths Are Treated Differently
A hunter finds the body of a young man in the woods. A detective, crime scene technician, and coroner arrive to search for signs of foul play. The site is taped off and an officer is stationed to prevent scene contamination. The exact posi- tion and condition of the body is documented. Potential evidence is collected.
What if a fisherman discovers this body underwater, and similarly, neither the cause nor manner of death is obvious? Our experience shows that accidental drowning is the most likely mindset for arriving personnel. The dive team is called in to recover the body, which may or may not be bagged as it is dragged to shore. Is the exact condition and location of the body documented, along with wind, current, and depth? Are water samples taken? Are detectives and a medical examiner called in? Are the underwater and shore areas taped off and searched for possible evidence? Many departments have to answer “no” to most or all of these questions.
Compare a dispatch for a toddler found dead at the bottom of the basement steps in her home with a call for a toddler found drowned in a bathtub. The cry- ing mother states that she went to answer the phone, was gone for less than 2 min, and, when she returned, found Sally not moving. How are these incidents man- aged? Are crime scene technicians called in? Is the house well photographed?
Are scene temperatures taken? Are family members, neighbours, and babysitters interviewed? Is the family checked for any previous child or spouse deaths? The answers are likely to be “yes” for the basement incident and “no” for the drown- ing. Without obvious evidence to the contrary, the occurrence of drowning is typically treated as a tragic accident.
The tendency to see drowning incidents as accidents may cause red flags and evidence to be missed at every level from first responders to medical examiners.
Compounding this is that drowning scenes present little or no typical signs of foul play. Victim trauma, signs of struggle at the scene, and signs of previous abuse, are not typically visible at pure-drowning homicide incidents where there has been no other violence or cause of death other than drowning.
Foul play is easily perceived when victims have a bullet in their head or bricks tied to their body, or when the available information is illogical. The vast major- ity of drowning homicides that do get reported in research papers and coroner reports involve additional forms of violence, such as strangulation, stabbing, or beating [1−8]. There is no evidence that the majority of drowning homicides include other forms of violence. Rather, it more likely demonstrates that police and medical personnel more frequently recognise such aggravated drowning homicide incidents, and miss, or fail to gain convictions on, pure drowning homicides.
Holding the head of a child underwater in a tub takes little effort. The little water splashed from the tub is easily wiped away. A non-swimmer pushed into deep water may not even have subcutaneous bruising. Pure drowning homicides can be medically undetectable, are effortless to perform, require no perpetrator skill, require little or no clean up, the body does not need to be disposed of, and the perpetrator often receives much sympathetic attention and possibly acciden- tal death life insurance money.
▬ A father calls for help when his 4-year-old son drowns in a bathtub. Deputies find the father performing CPR. The investigators, who had initially accepted accidental drowning, later obtain a confession of premeditated murder.
▬ An infant death is ruled as SIDS by an experienced medical examiner. A later tip sparks an investigation. The boyfriend of the mother drowned the infant in a sink because it cried.
▬ While on a boat with her family, a young girl falls out and drowns. Accidental drowning is ruled. Two years later the mother admits that the father hit the girl out of the boat.
The investigative mind should be kept alert when responding to drowning inci- dents. Hospital physicians should consider notifying police in each drowned pa- tient. Pathologists should routinely check the full torso for subcutaneous bruis- ing and other signs of foul play on drowning victims. This is especially impor- tant when there are no witnesses, the witnesses knew the victim prior to death, or when the drowning incident seems illogical. If examination of the lungs of the victim does not show evidence of water aspiration, other causes of death must be considered [9]. Departments should consider homicidal drowning investigation training.
It could prove helpful to use a standard incident form on all drowning inci- dents to better collect and recognise potentially valuable evidence of foul play.
This record would also provide research data.
12.5.3 Website
▬ www.rip-tide.org
References
1. Copeland A (1986) Homicidal drowning. Forensic Sci Int 31:247−252
2. Fanton L, Miras A, Tilhet-Coartet S, et al. (1998) The perfect crime: myth or reality? Am J Forensic Med Pathol 19:290−293
3. Lucas J, Goldfeder LB, Gill JR (2002) Bodies found in the waterways of New York City. J Forensic Sci 47:137−141
4. Missliwetz J, Stellwag-Carion C (1995) Six cases of premediated murder of adults by drowning.
Arch Kriminol 195:75−84
5. Oishi F (1970) A typical case of homicide and head injuries. Tokyo ika daigaku Zasshi 28:541−548
6. Pollanen MS (1998) Diatoms and homicide. Forensic Sci Int 91:29−34
7. Trubner K, Puschel K (1991) Todesfalle in der Badewanne. Arch Kriminol 188:35−46
8. Heinemann A, Puschel K (1996) Discrepancies in homicide statistics by suffocation. Arch Krimi- nol 197:129−141
9. Modell JH, Bellefleur M, Davis JH (1999) Drowning without aspiration: is this an appropriate diagnosis? J Forensic Sci 44:1119−1123
12.6
The Approach of the Pathologist to the Diagnosis of Drowning
Ian Calder
Drowning is defined by the 1978 Oxford Dictionary as “to perish by suffocation under water (or other liquid)” [1]. This encompasses a wide spectrum of environ- ments in which death can occur. In 2002, a group of international experts was con- vened at the World Congress on Drowning to update the definition of drowning.
Their consensus was “Drowning is a process of experiencing primary respiratory impairment from submersion/immersion in a liquid medium. Implicit in this def- inition is that a liquid-air interface is present at the entrance of the airway of the victim, preventing the victim from breathing air. The victim may live or die after this process, but whatever the outcome, he or she has been involved in a drowning incident” [2]. Water obviously is the most common medium for drowning. Never- theless, drowning can result in a wide variety of pathological appearances due to the physical, chemical and biological nature of the immersion fluid.
Survival following immersion in contaminated water may subsequently re- sult in complications and death. The features of this may be bacterial pneumonia with lung abscesses, but also atypical pneumonia with features of viral infection with inclusion bodies. In the industrial scenario there may be immersion or sub- mersion in fluids other than water, for example oil or solvents. The immediate physiological effect of aspiration of liquid is to reduce the oxygen exchange in the lungs. The confounding factors of the toxic effects of the chemical substanc- es must also be considered in these circumstances.
The scientific and reasoned diagnosis is one of the most difficult problems with which a pathologist has to deal, especially if there is a period of delay in the recovery of the body. Thus the only certainty is that there is a history of immer- sion. It is important that all immersion deaths are approached objectively with
the assimilation of facts and observations, thus facilitating a logical and defensi- ble conclusion (personal communication, GA Gresham, 1971). There may be no true stigmata of drowning and a clinical-pathological diagnosis may have to be made based on circumstantial evidence.
The following differential diagnosis should be considered in approaching the investigation of bodies recovered from water:
▬ Death due to drowning
▬ Death due to injury or other factors before entering the water
▬ Death due to natural causes during immersion such as sudden fatal arrhyth- mia or cardiac arrest
▬ Death due to injury during immersion
▬ Death due to other factors, such as hypothermia, during the time of immer- sion
External evidence of immersion discussed below should be taken into consid- eration:
▬ Skin slippage may commence within a matter of minutes following immer- sion in warm water, but this may extend to many hours, or days in cold water.
The early changes occur in areas where there is thickened keratin on hands, fingers and the soles of feet. The result is the development of wrinkling of the skin referred to as washer-woman skin. Such changes do not so readily affect skin protected by clothes.
▬ Immersion in cold water can result in the development of cutis anserina (goose flesh). The cause is contraction of the erector pilae, which are at- tached to the hair follicles. This causes dimpling of the skin. As there are other causes such as rigour mortis, the finding has to be regarded with some circumspection.
▬ The distribution of post-mortem hypostasis has little or no value in the di- agnosis of drowning, as there may be much variation of posture during the period of immersion or submersion.
▬ External contamination may give some indication as to the environment in which the body was submerged. Examination of fluid in the lungs is consid- ered later in the text.
12.6.1
Estimation of Time of Death
Estimation of time of death is an enigma of pathology and an aspect for which there is rather imprecise science. However, there are certain signs following im- mersion in temperate climates that may be helpful:
▬ Absence of wrinkling of the skin of hands: less than a few hours
▬ Wrinkling of the skin of hands and feet: 1−3 days
▬ Early putrefaction of exposed skin: 4−12 days
▬ Marbling of the skin with gaseous distortion of the face and abdomen:
14−28 days
▬ Liquefaction and early skeletonising: 2 months
These observations are extremely variable and may be modified by environmen- tal factors such as water contamination, water flow, temperature and animal in- terference.
12.6.2
Death Before Entering Water
Death before immersion has to be considered in the differential diagnosis of all cases of bodies recovered from water. At one end of the spectrum is the use of immersion to dispose of a body as the result of a crime. At the other end are natural causes causing involuntary fall into water. The diagnosis of ante-mor- tem injuries, such as from road accidents with vehicles becoming immersed, is an important factor in such investigations. In cases where the victim was dead before becoming immersed, there will not be signs of water aspiration in the lungs.
12.6.3
Immersion Other Than Drowning
Sudden immersion in cold water of persons who are intoxicated with alcohol is recognised as a cause of sudden death, with the mechanism possibly related to vaso-vagal inhibition or other fatal cardiac arrhythmias.
12.6.4
Autopsy Technique
It is not possible to be prescriptive on autopsy techniques, as pathologists have developed or been taught a fundamental technique, which is flexible and modi- fied for individual circumstances.
There are special findings, which have to be considered in immersion deaths in relation to diving. The ultimate diagnosis may be drowning, but the reason for such has to be carefully considered, as to why an individual well experienced in the aquatic environment dies. Factors such as equipment failure need to be considered, and the all-important effects of pressure physiology resulting in barotrauma. Simple palpation of tissues of the mediastinum or chest wall may give the characteristic crepitant feeling of surgical emphysema, reflecting the presence of gas in tissues.
Photographic or diagrammatic recording of external lesions is vital. Pneu- mothorax has to be included or excluded by appropriate technique. Diving is not necessarily a cause of pneumothorax as uncontrolled pressure changes of half a metre can provoke alveolar rupture [3, 4]. In 1921, Gettler suggested blood sam- ples be taken from left and right ventricles for electrolyte measurement to aid the differential diagnosis of fresh and salt water immersion [5]. Subsequent studies demonstrated this to be unreliable [6].
12.6.5
Autopsy Observations
There may be no abnormal findings in bodies found in the water. This leads to an unexplained sudden death. This happens, for example, in circumstances of sudden immersion in cold water, and the cause has been proposed to be vaso- vagal inhibition, producing cardiac arrest. There are no pathological findings in these cases. Although in these cases death occurs in water, it is not appropriate to classify such victims as having drowned. If these victims were alive when they entered the water, their death is likely due to a primary cardiac event, not as the result of submersion precluding respiration. Thus, dry drowning is not an appropriate label because these victims die of a fatal cardiac arrhythmia, not of respiratory impairment secondary to immersion/submersion [2, 7].
It has to be recognised that there are no specific features or markers of drown- ing. However, the finding of froth in the air passages lends support to the inhala- tion of water. The froth is formed by the mixture of water and air with proteina- ceous exudate and surfactant. It is usually white when submersion occurs in sea water; however, it may be pink or red-tinged due to rupture of red blood cells by the absorption of hypotonic liquid in the presence of hypoxia when fresh water is aspirated. This releases free haemoglobin into the plasma, which colours the pulmonary oedema fluid. The physical distribution of pulmonary oedema from drowning is somewhat different from that of cardiac failure as it may form a continuous column from trachea, bronchi, and bronchioli. The lungs in such cir- cumstances show oedema, with characteristic fluid exuding from cut surfaces.
External examination of the lungs frequently show hyperinflation with anterior fringes of the lungs overlapping. Petechial haemorrhages in the interlobular fis- sures of the lungs, face or eyelids are not a constant feature, but such findings must be taken into the appropriate clinical-pathological context.
The lungs of victims of immersion/submersion who have aspirated water may vary in weight from one victim to the next. However, as a rule, they are heavier than normal. In the experience of the author, lungs that weigh more than a kilogram usually do not reflect drowning, but some other cause of the oedema due to heart failure, especially in the case of post immersion shock due to hypo- thermia. Histology is non-specific, but the detail of the oedema is important to differentiate from inhaled or endogenous fluid. There may however be dilatation and rupture of alveoli. Amorphous and bi-refringent material due to inhalation of water may be present in the alveoli, and food particles secondary to aspiration of regurgitated stomach contents.
The appearances of the lung may be altered as a result of resuscitation. In view of the fact that dissection can confound the appearances, especially when it is necessary to identify the presence of gas, standard radiography is a useful diagnostic tool [8].
The following experiences are of proven value in the forensic laboratory ex- perience of the author:
▬ A definitive diagnosis of immersion and submersion can be helped by the identification of diatoms. These are organisms with a silica shell, which is resistant to both decomposition and concentrated acids. The principle of the
