SUN PRAIRIE, Wis. (AP) — One man is dead after a fire at a Sun Prairie apartment complex.

Firefighters responded to the blaze about 9:15 p.m. Sunday at a 16-unit apartment complex in Sun Prairie. After the blaze was extinguished, authorities found a body in a second-story apartment.

Charles Dean Cobb, 40, died of injuries sustained in the fire, the Dane County Medical Examiner’s Office said Monday. No foul play was suspected in the fire, although the cause of the blaze is still being determined, the Sun Prairie Fire Department said.

Fire and police officials, as well as an agent from the federal Bureau of Alcohol, Tobacco, Firearms and Explosives, are investigating the fire and what caused it. No damage estimate was given.

The building did not have sprinklers since it was built before the time sprinklers were required in apartment buildings, according to the Wisconsin State Journal.

Three residents were trapped in their first-story apartment and were rescued by firefighters; one of those residents was taken to the hospital for treatment. The fire originated in a second-floor apartment.