Recovering Evidence at Depth


by Dr. Thomas W. Powell:2 PS Divers recovering evidence

Evidence recovery is a primary function for almost all public safety dive teams in the United States. Team members often hope to be available to perform rescues or bring closure to families, but in truth, dive teams are frequently called in to look for evidence that may assist in a legal case. In many of these cases, law enforcement personnel have exhausted all other options and require a sub-surface team to search where others cannot. Essentially, a dive teams’ skills in regards to sub-surface evidence collection may be responsible for solving a case, or conversely, letting it slip through a detectives fingers.

Law enforcement officers are trained to handle evidence, and follow chain-of-evidence custody procedures to ensure any recovered items are handled in a manner that may allow those items to be admissible in a court room. The reality is that many dive teams are not made up of law enforcement personnel. In recent years, Emergency Response Diving International (ERDI) has made an effort to develop classes designed to better train public safety divers to follow chain-of-evidence protocols, and ensure proper evidence collection procedures. These efforts are apparent within courses such as the Underwater Crime Scene Investigation program. The objective of these types of courses is to train any public safety diver to document and handle evidence in a manner that follows standards required by law enforcement personnel and/or crime scene investigators.

Evidence collection is a process that can be time consuming and task heavy. First, team leaders and tenders must monitor dive times, gas consumption, and diver safety. Divers must be prepared to find, mark, and document any item. The location of an item must be mapped and documented, and any evidentiary photos or videos must be recorded. These actions take time, and can cause a diver to expend gas and energy. These levels of expenditure can create dangerous situations, which further demand attention from leadership and support personnel in regards to monitoring the safety of any sub-surface team member.

Deep diving brings complications into the process of evidence collection and recovery. Deeper depths and the possibility of more dangerous environments further reduce dive times. Similarly, gas may be consumed at a higher rate and physical exertion may increase due to mental distress or the potential effects of deeper water. Dive team leaders must plan and train for scenarios such as this, especially if the dive team is willing to take on any mission regarding evidence collection at deeper depths.

Dive team operating procedures must be developed for different types of missions at various depths. Essentially, if a diver consumes gas at such a rate that a 20 minute dive at 25 feet allows for enough remaining gas to return to the surface, deal with any minor foreseeable issues, and undergo decontamination, that same diver must be restricted to a shorter dive at deeper depths to account for increased gas consumption. The team must also plan for back-up or secondary divers to be prepared to complete any tasks not completed by the initial diver(s). If an item must be recovered that requires a heavy-lift capability, or lift bags, the team must also plan for the extra equipment, set-up time, and controlled actions to ensure essential evidence is not destroyed in the recovery process. These actions and processes must be streamlined.

Evidence collection is a process that can be tedious, but can also provide information that otherwise would not be available. Dive teams must take the time to understand the evidence collection process, and then practice this process until actions become fluid and methodical. In many cases, one might want to involve local law enforcement crime scene investigators in training operations. Personnel of this type may even be invited to participate in an awareness-level ERDI class to better understand how a dive team performs actions underwater. Finally, teams must also recognize where problems can occur and plan out emergency scenarios. No evidence is worth the life of a diver. If a team develops standards, practices those standards, and follows the evidentiary guidelines maintained by law enforcement departments, sub-surface evidence collection can be a valuable capability maintained by any public safety diving unit.

PS Divers at depth 2 PS Divers

-Dr. Thomas Powell – Owner/Instructor Trainer at Air Hogs Scuba in Garner, NC



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