7-year-old girl finds grandfather's hunting rifle, unintentionally shoots and kills her brother

7-year-old Halee Clark and her 10-year-old brother Christian were playing inside their grandfather's recreational vehicle outside of his home in Dix, Illinois. According to the sheriff their grandfather, Jason Clark, had opened up the camper so "the kids could watch movies and stay in the air conditioning."
Clark uses the RV as a hunting cabin and keeps it parked in a wooded area next to his house.
Halee picked up a loaded, unlocked long gun and unintentionally discharged a round. The bullet struck Christian in this face, killing him. Christian was pronounced dead at the scene.
According to the sheriff, "All indications are that this was a tragic accident. Foul play is not suspected at this time."