Local and federal law officers conducted an exhaustive manhunt in Shreveport-Bossier City today for Robert Leroy McCoy, the man accused of going on a murderous rampage Monday night, killing the mother and step-father of his estranged wife along with his teenage step-son.

The 34-year-old McCoy, who had been sought by police since he allegedly put a knife to his estranged wife's throat three weeks ago, remained at large late this afternoon. He is named in an arrest warrant charging him with three counts of murder.

His estranged wife Yolanda -- who had been involved in a contentious divorce with him and is believed to be the primary target of his rage -- was in protective custody today.

Killed Monday night at Patricia Plaza apartments in the Waller neighborhood were Christine Colston, 55; Willie Ray Young, 50; and Gregory Lee Colston, a 17-year-old senior at Parkway High School who was set to graduate next week.

The adults were found dead after a 911 call in which dispatchers heard a commotion in the apartment before the line went dead. Patrol officers were dispatched to the apartment and found the victims. 

The teenager died this afternoon after being removed from life support at the hospital.

Police Chief Mike Halphen said Gregory Colston had gone to live with his grandmother because his mother felt he would be safe there from her threatening husband.

McCoy and his estranged wife had been involved in a contentious, two-year divorce. She sought and got a protective order against him three weeks ago after telling authorities he had stalked and threatened her, court records show.

Yolanda Colston-McCoy, a mother of two, said McCoy had placed a knife to her throat and inflicted a small cut in mid-April, police said. Four days earlier, he had broken into her house and had cut her tires, she said in documents asking for the protective order.

Police believe one of the victims went outside to smoke Monday night and McCoy saw his chance to get inside the apartment. Halphen said he did not know if McCoy had reason to believe his estranged wife was inside.

Neighbors said Christine Colston and Young mostly kept to themselves. He was disabled but earned some extra money by detailing cars, a neighbor said.