Pittsburgh ? The body of a state trooper was found near his cruiser after he pulled over a car early Monday, police said.

Cpl. Joseph Pokorny was found dead about 2 a.m. near an exit of Interstate 279 about 5 miles southwest of the city, officials said.

“I just want to say that we are going to work this investigation until the suspects involved in this cowardly murder are behind bars,” said state police Col. Jeffrey B. Miller.

Pokorny, 45, who had been a trooper for more than 22 years, was found by a Carnegie borough police officer. The officer saw Pokorny’s car door open and found the trooper’s body outside the car.

Pokorny had called in information on a black 2001 Mercury sedan minutes earlier, and police were reviewing tapes of the call to determine why he had pulled it over.

Police were also looking for the sedan, while officers from several departments joined in a manhunt in woods near the shooting, authorities said. Police said the trooper’s gun was also missing, although they couldn’t say if that was the weapon used to shoot Pokorny.