A man accused of killing a key witness to the April slaying of a 12-year-old boy surrendered to Allegheny County sheriff's deputies last night at the urging of his family.

Jesse Engram, 19, of East Liberty, is charged with homicide in the Monday night shooting of Korey Johnson, 20, near the gas pumps of a Sunoco A-Plus station at Penn and Brushton avenues in North Point Breeze.

Investigators issued a warrant for Mr. Engram's arrest on Wednesday. His relatives brought him to the sheriff's office about 5:45 p.m., and turned him over to authorities, sheriff Lt. Jack Kearney said.

Mr. Engram's arrest may have implications in another fatal shooting that shocked and saddened Wilkinsburg residents in April.

Mr. Johnson told a judge in April that he was the target when Donald "Tank" Wilson opened gunfire on the From Head 2 Toe clothing store in Wilkinsburg. Mr. Johnson was not wounded by the gunfire, but a 12-year-old boy, Kholen Germany, died in the shooting.

Mr. Wilson is in the Allegheny County Jail awaiting trial for homicide in Kholen's slaying.

Korey Johnson's brother, Kevin Johnson, 23, who also was at the scene of the shooting, is said to have returned Mr. Wilson's fire. Kevin Johnson is in jail, awaiting trial on charges of illegal possession of a firearm and carrying a firearm without a license in that shooting. He has not been charged in the boy's death.

It was unknown last night whether Korey Johnson's slaying is related to Kholen Germany's death, or how Mr. Engram knew Mr. Johnson. A motive for the Monday night killing was also unknown.

Court records show Mr. Engram was also arrested in September 2007 for simple assault.

Pittsburgh police, who questioned Mr. Engram for several hours last night, said Allegheny County homicide detectives, who are investigating the Wilkinsburg shooting, also wanted to speak with him. He was scheduled to be arraigned late last night.

After Mr. Johnson was shot several times while in the driver's seat of a purple GMC Yukon parked at a pump, police said they chased a suspect toward East End Avenue but lost sight of him. A passenger accompanied Mr. Johnson but was inside the convenience store when the shooting occurred.

Mr. Johnson was pronounced dead at the scene. He was awaiting trial for possession of heroin with intent to distribute, and also pleaded guilty to drug possession in 2007.

At a May preliminary hearing, Korey Johnson told a judge that he and Mr. Wilson had an ongoing feud over a woman, and Mr. Wilson had shot at him and missed once before.