One morning, in a hospital in the Czech Republic, a 69-year-old man died of heart disease. An hour later, as nurses were preparing to move his body down to the lab for autopsy, they noticed his skin was unusually warm. After calling the doctor back to make sure the man was really dead (he was), they took his temperature. At 1.5 hours after death, the body was 104 degrees Fahrenheit—about five degrees hotter than it was before he died, even though the hospital room was kept at about 68 degrees.
Fearing the body might spontaneously combust, the doctor and nurses took pains to cool it with ice packs, and eventually it got as chilly as one would expect of a corpse. This interesting case-study is published in the American Journal of Forensic Medicine and Pathology, and in fact has nothing to do with spontaneous combustion.
“Post-mortem hyperthermia is a well-documented phenomenon, but it's not well understood," says Victor Weedn, a forensic pathologist at George Washington University. Although it's mentioned in forensic science textbooks, “It's not necessarily known by a lot of people.”