MERCER, Pa. (December 9, 2012)--A 7-year-old boy who was killed when his father's gun went off outside a gun store was buckling himself into a safety seat in the man's truck when he was shot, state police in western Pennsylvania said.

The boy was shot Saturday morning at Twigs Reloading Den in East Lackawannock Township, 60 miles north of Pittsburgh.

State police say the boy's father, Joseph V. Loughrey, 44, didn't realize a bullet was still in the chamber of the pistol.

Craig Allen Loughrey, 7, was shot in the chest as he buckled the safety seat in the truck’s backseat.

Lt. Eric Hermick said Sunday the father secured a rifle in the back of the truck and placed a pistol on the console when the handgun went off.

Hermick says the father had been trying to sell the guns.