on police or crime TV shows such as C.S.I. , the forensic investigator often asks, "what is the TOD?" this refers to the time of death or the exact moment when a person died. organs that respond most quickly to changes in body temperature are the liver and the brain, and it's due to their mass and density. by analyzing these organs, a coroner can tell the TOD. after death, a person's body temperature starts to lower to that of the surrounding environment at a rate of 1.27 degrees celsius per hour.