A suspicious death investigation is underway after a body was found Sunday morning by crews responding to a small fire at a Mehlville apartment. The St. Louis County Police Department said officers responded shortly before 9 a.m. to the 4000 block of Nottingham Estates Drive for a report of smoke at an apartment building. The building was evacuated and first responders put out a small fire inside an apartment. A man was found dead in the apartment. Police haven't released his identity or cause of death. The department's Bureau of Crimes Against Persons, the St. Louis Regional Bomb and Arson Unit, and the Crime Scene Unit are leading an investigation.