PITTSBURGH — A state trooper who killed an unarmed 12-year-old boy in 2002, leading to a $12.5 million state settlement, was one of two police officers involved in a fatal police shooting during a weekend drunken-driving patrol.

Trooper Samuel Nassan III is under investigation for firing at Nicholas Haniotakis, 32, of Pittsburgh, about 1:30 a.m. Sunday on the city’s South Side, state police spokesman Jack Lewis said.

An autopsy shows Haniotakis died of gunshot wounds. A trooper and a city officer who were taking part in roving DUI patrols fired at Haniotakis, according to a news release from Pittsburgh police.

Nassan, 36, of Pittsburgh, declined to comment when reached on his cell phone Monday by The Associated Press.

“Don’t be calling this number again,” Nassan said. “Right now I’m going to go file a complaint on you for calling this private number.”

Nassan will remain on administrative desk duty while Allegheny County District Attorney Stephen Zappala Jr., city police and state police review the shooting, Lewis said. The removal from patrol duty is routine for officers who shoot someone on duty.

Nassan was one of two troopers sued for the Christmas Eve 2002 shooting of Michael Ellerbe, 12, of Uniontown.

A federal court jury in Pittsburgh found last March that Nassan and Cpl. Juan Curry fired at the boy as he ran from a stolen sport utility vehicle the troopers were chasing.

The jury awarded Ellerbe’s father, Michael Hickenbottom, more than $28 million, but the state police appealed. The case settled for $12.5 million in November — by far the most ever paid by the state police in a wrongful shooting.

The city officer involved in the shooting, identified by police as Sgt. Terrence Donnelly, is on paid administrative leave, which is routine for Pittsburgh police involved in shootings.