Some weird, morbid trivia:
After a person dies, their body will usually start to cool down. Except, not always. Sometimes the body of a recently deceased person will actually rise in temperature. The phenomenon is known as "postmortem hyperthermia."
A recent article in the American Journal of Forensic Medicine and Pathology
described a case that occurred in the Czech Republic, involving a guy who died of heart disease, while in a hospital:
According to the Czech law, the deceased must remain in the hospital ward for 2 hours after death. In this case, the ambient temperature in the hospital room was 20ºC. One hour after death, nurses started to prepare the body for transport to the Department of Pathology. They noticed the unusually warm skin of the deceased, and a doctor was called back to the hospital room to verify death again. The first record of postmortem body temperature was noted in 1.5 hours after death and peaked at 40.1ºC. Remarkably, the medical staff had concerns about spontaneous combustion of the body and attempted to cool the body with frozen solutions placed near the groin.
Source: "Postmortem Increase in Body Core Temperature"
Am J Forensic Med Pathol - 38(1), Mar 2017
Scientists really aren't sure what causes postmortem hyperthermia, but the list of possible causes includes: "pathological processes," violent incidents resulting in hidden cerebral traumatism, brain trauma with cerebral hypoxia, death by asphyxiation, and excited delirium.
More info: popsci.com