SANDY CREEK TWP, Venango County — A 13-year-old boy is accused of fatally shooting his grandmother and stepgrandfather Sunday afternoon at their home on Polk Cutoff in this township about 15 miles north of Clintonville.

State police said Zachery J. Proper of Oil City was arrested Monday night and charged with two counts of homicide.

Investigators suspect the boy shot Dorothy E. Fross, 67, and George Alvin Fross, 69, with a semi-automatic pistol — possibly a 9 mm — about 4 p.m. He then allegedly took the couple’s car.

George Fross had been shot multiple times, authorities said. It was not immediately known how many times his wife was shot.

“They both appeared to be victims of gunshot wounds,” said Venango County Deputy Coroner Chris Hile, who along with Coroner Tyler Best pronounced the Frosses dead at 5 a.m. today.

Dr. Eric Vey, an Erie County forensic pathologist, was to conduct autopsies this morning.