Sea drifting cadavers: cases of the point and time of disaster entry

Estimating the point of entry and the timing of ocean-drifting human bodies is an important issue for forensic investigation. This study examined bodies found drifting off Kanagawa Prefecture and the Izu Peninsula that had been subjected to medicolegal autopsy. Of 124 autopsy cases commissioned by the Third Regional Coast Guard Headquarters during 2007–2016, 94 cases (76％) were identified, although the point of entry and the timing had been specified in only 10 cases (8％). The cause of death was suicide in 2 cases. The other cases were accidents, such as those occurring during swimming. Long-distance drifting of more than 50 km was observed in 3 cases. In all 3 cases, the accumulated degree days were more than 120℃. Putrefaction had progressed. In one case, the body had drifted 580 km on the Pacific Ocean in 13 days. The drifting distance was correlated with the postmortem submersion interval among drifted cadavers in the ocean currents (r=0.97). A growing need exists for estimation of the point of entry and the timing of ocean drifting bodies in Japan, which is surrounded by large sea areas. We intend to construct a logical analytical system using these actual cases as basic data.