A man was found dead on the sidewalk outside his apartment on Tidwell at Guhn just after 5am Sunday.
Houston police officers arrived at the Villa Anita Apartments to find the 38-year-old victim with two gunshot wounds to the head.
Police said the man and his wife had four or five friends over Saturday night. They believe the man who killed the victim was one of those friends.
As hours passed, investigators pieced together what happened inside the apartment.
They said the gunman and his girlfriend were fighting, and the victim got in between them to stop it. The fight moved outside the apartment where the suspect allegedly pulled out a gun and shot the victim.
Police spent the day interviewing witnesses who saw their friend's murder. They confirmed no one else was hurt, but said an infant was inside the apartment at the time of the shooting.
Now, they're turning their attention to a man they call a person of interest -- Rodney Wayne Allen, 21.
"He knows who he is. He left the scene in a vehicle. We need to talk to him. We need to get his side of the story," HPD Homicide Sgt. W.L. Meeler said.
The victim's name has not been released.
Anyone with information on Allen's whereabouts should call police.
Please stay with Eyewitness News and abc13.com as we continue to follow this developing story.