They arrested Richard Brandon Gregory, 28, Tuesday night. He's accused of killing 64-year-old James Melvin Jolly in a domestic dispute.
The shooting happened just after 2:20 p.m. Tuesday in the 100 block of Coley Farm Road.
According to an arrest warrant obtained by ABC11, Gregory was administering CPR to Jolly when police and paramedics arrived.
He admitted to the shooting and said he and his stepfather were arguing and the older man came at him and started shoving him. He said he drew his firearm and shot Jolly after several warnings.
The warrant says investigators found a .45 caliber Smith and Wesson handgun.
Gregory was taken to the Wake County jail. He's being held without bond.