Donald Watson, 74, was found at 4424 Regis Ave.
A caller to 911 described a bloody scene, saying Watson's face was covered in blood. But the caller was unsure whether Watson had been attacked or had simply collapsed and hit a bookcase, saying there was shattered glass on the floor near his body.
Police classified the death as a homicide Tuesday, but did not release details about how Watson died.
Anyone with information is asked to call 919-560-4440, ext. 29341 or Crime Stoppers at 919-683-1200. Crime Stoppers pays cash rewards for information leading to arrests in felony cases and callers never have to identify themselves.
Neighbors said police have told them there is no reason they should be concerned for their safety. They said Watson was a beloved part of the community.
Watson worked for the Durham Fire Department from 1959 to 1992. He retired as a fire captain.