Port Authority police yesterday were trying to find the person who fired a bullet through the rear window of a bus in Brighton Heights, hitting a passenger in the chest.

James Raglin, 27, of Homewood, was taken to Allegheny General Hospital after the 12:35 a.m. incident on the 500 Highland Park-Bellevue bus. He was in stable condition with the bullet lodged in his chest.

Pittsburgh homicide detectives, who respond to serious shootings, were initially investigating with Port Authority police but later turned the case over to authority officers when it became clear that Mr. Raglin was not critically injured.

Bob Grove, Port Authority spokesman, said the shooting was the first of its kind in his 8¹/₂ years at the authority -- and maybe in its history.

"I've not talked to anyone here who can remember it happening before," he said. "No one's ever been shot on a bus."

Mr. Raglin, who lives on Susquehanna Street, was shot while the bus was stopped at a traffic light on Termon Avenue.

Police don't know if the shooter was targeting Mr. Raglin or someone else on the bus, or was shooting for some other reason.

In addition to Mr. Raglin and his nephew, Robert Raglin III, 20, of the North Side, there were three other passengers on board. None of them was injured, and none saw where the shot came from.

Police did make an arrest, however -- that of Robert Raglin.

Officers discovered he was wanted on an outstanding warrant in connection with a robbery in August that Port Authority police investigated. Court records also indicate that Pittsburgh police arrested him several times last year on drug and weapons charges.

Mr. Grove said the bus driver heard a bang, after which the Raglins approached him and asked to be let off the bus. He saw that Mr. Raglin was bleeding and tried to persuade the two to wait for help, but both insisted they be let off, so he let them go.

After they departed, the driver turned onto Termon and drove a few blocks while he called for help on his radio, then pulled over. The Raglins apparently had a change of heart, because they caught up with the bus after deciding to wait for paramedics and police after all.

Robert Raglin was being held in the Allegheny County Jail.