“Gun owners who don’t properly secure their firearms are just a second away from one of these tragedies happening in their home,” he said. The shooting, at a residence on the outskirts of Pine Bluff, remains under investigation, the sheriff’s office said. Pine Bluff, a city of about 40,000, is located 44 miles south of Little Rock. The Arkansas Department of Human Services was notified of the shooting and arrived at the home to help assess the welfare of the children in the home. The boy’s body will be taken to the state medical examiner for an autopsy, the sheriff’s office said. There have been at least 126 unintentional shootings by children in the U.S. this year — killing 55 and injuring 78 others, according to the nonprofit Everytown for Gun Safety. Last year there were at least 392 unintentional shootings by children, resulting in 163 deaths and 248 injuries. CNN’s Aya Elamroussi contributed to this report.