A 70-year-old man died of natural causes before he was found by authorities Tuesday who were responding to a carbon monoxide leak at a Hyde Park apartment building, authorities said.
Emergency crews responded to the building after a carbon monoxide alarm went off about 9:20 p.m. in the 800 block of East 53rd Street, Chicago police said. While they were evacuating the residents, firefighters noticed a stove turned on in the unit where the alarm was going off.
A man in the apartment across the hall was found unresponsive and pronounced dead at the scene, police said.
Preliminary information from police suggested the death was related to carbon monoxide, but an autopsy from the Cook County medical examiner's office found the man died from heart disease.
Fire officials said the area was being treated as a crime scene, but police said there was no preliminary information that suggested foul play.