Police have identified the man who was killed at the Bristol Park Apartments last night.
Michael Howell, 46, was found shot to death inside his apartment late Sunday night.
Witnesses say four masked men were seen running from the apartment.
Police found five bullet holes in the door.
"I really think that when we get into it, we are going to find the reason is something to do with our victim," said Sgt. Dave Walker of the Tulsa Police Department.
Police say the victim never opened his door and shooters stood outside and fired.
"We are going to have to keep plugging along. Somebody knows something. If there are four people involved in this, the chances somebody knows something is going to be great," said Walker.
Investigators say the victim was from Michigan. His family arrived at the apartment Monday morning.
Neighbors say the victim was friendly and that the murder has shaken them.
"It really was a shock that somebody had done that. I don't know if somebody tried to rob him, or somebody had a bad temper with him, or what," said Jackie Asberry, a neighbor.
This makes the 22nd murder so far this year in Tulsa.
"This has been a bad run, the last couple of weeks. We have three in the hospital that could die, and that would jump our numbers up again. We are rapidly catching up with last year," said Walker.
Police say it will take help from the public to solve this case.