Chaparral, N.M. ? Investigators in New Mexico say a Chaparral man who was cleaning his handgun Saturday morning accidentally shot his 4-year-old son and the bullet passed through the boy and hit the man’s mother.

Dona Ana Sheriff’s Department investigator Bo Nevarez says both are in critical condition but their wounds aren’t believed to be life-threatening.

He says the bullet struck the boy in his stomach and continued through to the grandmother and hit her in the abdomen.

Investigators regard it as an accident but are sending the case to prosecutors to determine whether negligence played a role.