Some additional information about environmental conditions and their impact on the recovery rates of cadaver dogs––
While bodies at depths of 180 feet (approximately 78psi) may never achieve flotation because the decompositional gases being released are insufficient to even reach natural buoyancy (i.e., zero weight), bodies in shallower depths will tend to rise to the surface (
Osterkamp 908). The rate at which decompositional gases are released, and thus the rate at which a body will float, are strongly influenced by water temperature as well. At temperatures in the range of 30 degrees F, a submerged body may take months to the surface due to the extremely slow rate of decomposition, while a body submerged in water around 80 degrees F will decompose much faster and may float within a day or two (
Osterkamp 908).
When it comes to cadaver dogs, it is important to understand that scent in not distributed in a linear manner. The scent from submerged human remains does not necessarily rise straight up to the surface of the water, but instead may be carried by the flow of the water a few feet to a great distance away from the body (Dorriety 720).
Even when a body is submerged under a significant amount of water, cadaver dogs that are specially-trained in water recovery can still pick up the scent. In one case, water-trained search dogs consistently alerted to a specific location in the lake and police used sonar to look for anomalies to indicate the presence of a body, but were unable to find any evidence of a body (
Ruffell and Powell 130). Despite this, the police deployed a dive team to search the area of the lake the dogs alerted to and found the body of the missing man buried underneath a layer of silt at the bottom of the lake (
Ruffell and Powell 130-1). Some cadaver dogs have also been able to locate the remains of drowning victims
250 feet beneath the water.
IMO, if Brian committed suicide shortly after entering the reserve, his body probably would have floated to the surface by the time police began searching the area (barring any predation)––even with the flooding, the water level looked to be a few feet at most, hardly enough pressure to weigh down a body. Additionally, given the warm air temperature and (I'm assuming) the relatively high temperature of the water, any remains would decompose and surface quickly, releasing the gases cadaver dogs use to sniff out corpses. I find it a bit hard to believe that cadaver dogs would not have alerted to the area in the early days of the search (if, in fact, the police previously searched that area) if Brian was already deceased, MOO.
Sources
Callahan, Marion. "
Cadaver dogs sniffed out bodies 12 feet deep."
Morning Call [Allentown], 23 July 2017, pg. A10.
Dorriety, Jonathan K. "Cadaver Dogs as a Forensic Tool: An Analysis of Prior Studies."
Journal of Forensic Identification 57, no. 5 (2007): 717-725.
Osterkamp, Tom. "
K9 Water Searches: Scent and Scent Transport Considerations."
Journal of Forensic Sciences 56, no. 4 (2011): 907-912.
Ruffell, Alastair. "Lacustrine flow (divers, side scan sonar, hydrogeology, water penetrating radar) used to understand the location of a drowned person."
Journal of Hydrology 513, no. 26 (2014): 164-168.
Ruffell, Alastair, and Neil Powell. "
Search Strategy for Buried Objects in Water: Geophysics, Probes and Dogs."
Forensic Sciences 1, no. 3 (2021): 130-137.
