James Adams was a regular at the Fort Pitt Inn in North Fayette, where he worked some nights as a karaoke DJ. But on Sunday night, he was there checking up on a friend, a bar employee who had recently lost a loved one.
Shortly before 12:45 a.m. Monday, a man inside the bar walked out and returned with three handguns. He began firing, police said, injuring two men and fatally shooting Mr. Adams, 29, in the head.
"He was my only son," said his father, Edward Adams of Clinton, his voice breaking. "I'm going to miss him terribly."
Allegheny County Police Lt. Andrew Schurman said 25-year-old David Mazzocco of Imperial started shooting in the Steubenville Pike bar, shortly after a heated text-message exchange with his girlfriend.
Mr. Mazzocco's night began with dinner at a friend's place, where a witness told police he was showing the guns to guests there, according to a police criminal complaint.
At the end of the evening, the witness said Mr. Mazzocco put four guns -- three handguns and an AR-15 assault-style rifle -- in his truck. Police said Mr. Mazzocco told them he dropped off his girlfriend at her house after dinner, then headed, alone, to the Fort Pitt Inn, police wrote in the complaint.
None of the handguns was registered to Mr. Mazzocco, who county police said was barred from owning guns.
According to the criminal complaint, Mr. Mazzocco told them two handguns belonged to his mother, and the other he borrowed from a friend. Mr. Mazzocco lived with his mother, Gloria, in Imperial.
Asked why he shot the people in the bar, police said he told them he didn't know.
Mr. Mazzocco, who is the father of young twin girls, is in the Allegheny County Jail and has been charged with homicide, attempted homicide, two counts of aggravated assault, 11 counts of reckless endangerment and weapons violations.
Investigators believe he was having relationship problems via text when he left the bar upset by the conversation.
He returned with three handguns, ordering two friends in the bar to get out. They hesitated, and Mr. Mazzocco pointed a gun at one of them before they left, Lt. Schurman said.
Mr. Mazzocco started shooting, hitting three people inside, Lt. Schurman said. Two people were shot in the head: Mr. Adams and Joseph Quirk, who is in critical condition but suffered no brain damage, police said.
Bar customer Gerald Maroni fought back, disarming Mr. Mazzocco, who shot him in an arm. He and another customer, Juan Rodriguez, held Mr. Mazzocco on the ground for officers, county police said.
Lt. Schurman praised their efforts, calling both men courageous.
"Obviously it could have been a lot worse," Lt. Schurman said.
Police do not believe the nine or so bar customers inside had any connection to Mr. Mazzocco or were specific targets of the gunfire, Lt. Schurman said.
Edward Adams said his son was living with a friend in Imperial and also worked at a local convenience store. He was on the mend after a medical problem and was just getting his life back together.
"My son truly was a loved person," he said.