The event planners had me working the next day. A class of regional law enforcement met the first morning. I fear that most thought this class would be similar to their previous scuba classes; they were in for a surprise. We were about to embark upon a journey that departed from standard scuba instruction in some significant ways.

The first day dealt with the evidentiary foundations of underwater evidence recovery and crime scene processing. They learned that we package all evidence from water, in the water. Marine archaeologist place all their artifacts in the water in which they are found, and if it works for them it will work for us. We talked about possible forensic evidence and its survival underwater, including:

• The recent work on salt etched fingerprints on cartridge cases.
• Back spatter on firearms
• Fingerprints on and in firearms and on automobiles
• Processing submerged vehicles and raising them to the surface
• Body sink rates (how to calculate how far a body may float downstream before reaching the bottom)
• Processing a mass disaster underwater crime scene (passenger aircraft crashes)

The second day covered the operational aspect of evidence recovery diving. We talked about tethered diving and its departure from standard scuba procedure. We covered packaging underwater evidence, bagging bodies, and communicating with the line tender via line tugs. We talked about underwater measurements and crime scene sketches, and we discussed emergency procedures and team composition and roles.

We spent the following day at Gab Gab beach on the Guam Naval Base. Each participant had to demonstrate proficiency in conducting a shore-based search, maintaining search line integrity, and bagging a body: first with the use of sight, then with their face masks blacked out. The work we do is often called “black water” diving in that most of what criminals dispose of, they dispose of in very nasty places. Hence, the need for blacked out face masks.

The last day was the final examination. The students formed four teams and were dispatched to a scene where they were informed that a witness saw someone throw a gun into the water. It was their responsibility to interview the witness, conduct the dive briefing, select the appropriate search pattern, and to deploy, find, package, measure, and sketch the operation. Each diver on each team had to search before the firearm was discovered. It was hard work, but all felt they had accomplished something upon completing the final examination.