Skeletal remains that were found four months ago in a discarded couch along a Brooklyn highway belonged to a man who was killed by a sharp instrument, officials said.

“The cause of death is homicidal violence including sharp force injuries of torso and neck,” Chief Medical Examiner Dr. Barbara Sampson said. “The manner of death is homicide.”

A city Department of Transportation employee found the remains on Sept. 25 when they fell out of a couch left along the Belt Parkway in Marine Park, police sources said. The man’s identity wasn’t immediately released.