Heavy flames shot out the window of the Shore Road apartment just after 1 a.m. Monday. Firefighters quickly put it under control.
Police had been in the building earlier in the day for a man in his 70s who had died.
Neighbors were complaining of the odor. He lived alone and was described as a hoarder.
It was not clear how long he was dead but his death is not considered suspicious.
As building management waited for the body to be removed, the fire broke out and as many as six apartments in the building sustained water damage.
The cause of the fire is under investigation.
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