Almost a month after his body was found slumped in his wheelchair next to a dumpster, Atlanta Police are still trying to solve the mystery of who killed 45-year-old Olden Cooper.

11Alive's Faith Abubey was out with Atlanta Police Department Wednesday afternoon as detectives went back to the crime scene to canvas the area where Cooper was found, asking anyone with possible clues to come forward.

Lead investigator Detective Arthur Fernhorn told 11Alive the 45-year-old wheelchair-bound father was murdered in cold blood, apparently for no reason, his lighter still in his hand.

Wednesday was Fernhorn's sixth time at the apartment complex off Hollywood Drive in Atlanta since Nov. 18.

It was that day that dispatch came across his APD radio, around 1:30 a.m., to say someone found a man in a wheelchair shot in the head. It was Cooper, a father and a brother, and no stranger to many who lived in the apartment complex.

For weeks now, Cooper's brother Alfonso Bussie hasn't been able to take the obituary for the 45-year-old off his dashboard.

"I mean, what possibly could he have done to you, but said something to make you mad," Alfonso told 11Alive.

That's one thing about the case that's baffling to Fernhorn, "from everyone we've talked to, Mr. Cooper didn't bother anybody," he said.

Fernhorn said there were three witnesses that day who happened to be pulling in the parking lot when the suspect shot Olden in the head, but the gunman turned the gun on them and fired five times in their direction.

They ran before getting a good look at the suspect, and so far, they haven't been able to give police any other description other than what clothes he was wearing.

Since then, APD's calls for information have yet to turn up any fruitful leads, but they remain hopeful that with each knock, they'll get that much closer to finding a potential witness and answers who'll help break the case.