By Associated Press Published: Dec 8, 2012 at 4:13 PM PST Last Updated: Dec 8, 2012 at 5:40 PM PST

A man’s handgun went off while he was holding it as he got into his truck in the parking lot of a western Pennsylvania gun store Saturday, and the shot killed his 7-year-old son, authorities said.

Joseph V. Loughrey, 44, of Sharpsville, was getting into the truck when the 9 mm handgun discharged, wounding Craig Allen Loughrey in the chest, according to state police. The boy died at the scene at Twigs Reloading Den in East Lackawannock Township, 60 miles north of Pittsburgh.

Investigators said Loughrey told them he didn’t realize there was a bullet still in the chamber. “This happens all too often where people think the gun was empty,” Lt. Eric Hermick told The Pittsburgh Tribune-Review.

Loughrey was trying to sell two guns at the store – one a scope rifle and the other, the handgun, state police said. The owners told Loughrey the store doesn’t buy guns so Loughrey and his son returned to the truck with them. Loughrey put the boy in the passenger seat and loaded the rifle into the truck, state police said. He was attempting to get inside and reached to put the handgun in the center storage console when it fired, they said.

Loughrey was questioned by state police, who said he was cooperative and distraught. The shooting is being investigated as an accident, although Loughrey could face charges, including manslaughter and negligence, Hermick told the Pittsburgh Post-Gazette.

“I know that little kid was everything to him,” Mark McLaughlin of Fredonia, a friend and co-worker of Loughrey’s at Superior Well Services in Fredonia, told the Tribune-Review.

Messages left for the coroner’s office and at a listing in Loughrey’s name were not immediately returned.