Columbus Police investigating human remains found inside a north Columbus apartment building. Get the story.

Columbus Police have a mystery on their hands after human remains were found inside a north Columbus apartment building.

The remains were found early Wednesday inside a building in the 1600 block of North 4th Street, just east of the Ohio State University campus.

Detectives say it was reported after a neighbor discovered an odor coming from the home and became suspicious.

A woman who knew the home’s resident went inside, made the discovery, and called 911.

“All I seen was someone laying there, by the floor, the back of them,” said Melanie McCoy.

“There was extreme decomposition that is presenting challenges for the investigators,” said Sgt. Rich Weiner, Columbus Police Department.

Police removed the body and had it autopsied in hopes of trying to find an identity, a cause of death, and determine how long the body had been there.

“It's going to be months that we're talking about, not weeks or days,” added Weiner.

Melanie said she saw her friend, who lived at the house alone, just last week. She’s still very worried that it could be him.

While the identity of the person and the cause of death have not been determined, it appears there are persons of interest in the case.

Investigators say two men were seen leaving the building on Tuesday before the body was discovered.

“We're treating this as a homicide. That doesn't mean it was a homicide, but until we find out otherwise, we're going to investigate it as such,” added Weiner.