PITTSBURGH (AP) - A sheriff's deputy who was one of four officers who shot a child rape suspect, killing him, has been fired for allegedly having cocaine in his system at the time and could face criminal charges, authorities said Wednesday.

District Attorney Stephen Zappala Jr. said the deputy involved in the Jan. 6 shooting of 47-year-old Leslie Sapp III in Pittsburgh had tested positive for cocaine immediately afterward and could face criminal charges if additional tests show he was under the influence of cocaine at the time.

Zappala did not identify the officer.

But a law enforcement official familiar with the investigation identified him as Deputy Richard Dwyer. The person spoke to The Associated Press on condition of anonymity because the investigation is ongoing.

The solicitor for the Allegheny County Sheriff's Office had said only that Dwyer was fired for a policy violation.

Dwyer didn't answer calls to his home and his union representative didn't return a message seeking comment. An arbitrator is scheduled to hear a union grievance on Friday challenging his firing.

Law officers involved in shootings are automatically tested for drugs and alcohol, Zappala and Pittsburgh police Chief Cameron McLay said.

Zappala said the fired deputy could face charges if additional tests show he was under the influence of the drug, and did not just have traces of it in his system when Sapp was shot.

"So this is a serious matter, and that's part of the analysis we've directed the police to take," Zappala said.

The prosecutor's office last month announced that Sapp was hit with seven bullets from two weapons, but on Wednesday it clarified that Sapp was shot with four weapons of two different calibers.

The task force team sent to arrest Sapp in a pre-dawn raid included the fired deputy, a state trooper, a state probation and parole officer, and several deputy U.S. marshals, Zappala said.

Sapp had been charged in July with repeatedly raping a young girl starting in 2011.

The task force officers said they forced their way into his home after knocking repeatedly and getting no answer.

The officers have all said Sapp was shot as he came down steps from the second floor "with both hands on what they thought was a weapon" but which turned out to be a BB gun that resembled a pistol, Zappala said.

The trooper fired two rounds from a shotgun that missed, while the sheriff's deputy fired a .45-caliber handgun, and three deputy marshals each fired their .40-caliber handguns.

In all, 15 shots were fired from the handguns, seven wounding Sapp, with the fatal shot - through the heart - coming from one of the .40-caliber weapons, Zappala said.

That means investigators are sure Dwyer didn't fire the fatal shot. But Zappala said the fired deputy could still face criminal charges, including involuntary manslaughter, a first-degree misdemeanor punishable by up to five years in prison.

"There are other theories that, being hit seven times, the accumulation of that many hits was fatal," Zappala said.

The crucial question for the fired deputy is whether he was under the influence of cocaine when he fired, Zappala said.

"It has to affect his ability to react, to perceive, those sorts of things," Zappala said. "I want an opinion from a toxicologist, absolutely."

McLay, the police chief, said the investigation must still determine whether the deputy merely had cocaine residue in his urine, or whether he was actually under the influence of drugs when the shooting occurred.