Detecting Submerged Bodies: Controlled Research Using Side-Scan Sonar to Detect Submerged Proxy Cadavers

Forensic investigators routinely deploy side‐scan sonar for submerged body searches. This study adds to the limited body of literature by undertaking a controlled project to understand how variables affect detection of submerged bodies using side‐scan sonar. Research consisted of two phases using small and medium‐sized pig (Sus scrofa) carcasses as proxies for human bodies to investigate the effects of terrain, body size, frequency, swath width, and state of decomposition. Results demonstrated that a clear, flat, sandy pond floor terrain was optimal for detection of the target as irregular terrain and/or vegetation are major limitations that can obscure the target. A higher frequency towfish was preferred for small bodies, and a 20 m swath width allowed greater visibility and easier maneuverability of the boat in this environment. Also, the medium‐sized carcasses were discernable throughout the 81‐day study period, indicating that it is possible to detect bodies undergoing decomposition with side‐scan sonar.