A toddler in Payson, Arizona accidentally shot and killed his younger brother on Tuesday.
According to CBS5, the three-year-old got a hold of the weapon and fatally shot his 18-month old sibling in the head.
AZ Family News reported that the child’s mother and her two sons were visiting an elderly neighbor’s apartment when the children found the unsecured semi-automatic gun in another room.
After the single shot was fired, several calls went out to 911 and when police arrived they found the distraught mother carrying the wounded child out of the apartment.
The victim was pronounced dead at a nearby hospital.
Police found several weapons in the home of the 78-year-old neighbor and are still investigating the incident and questioning him.
"We still intend to serve a search warrant at that location and gather further information," said Payson Police Chief Don Engler.
Authorities have not released the names of the neighbor, mother or her children.
Payson is located in eastern Arizona about an hour and a half outside of Phoenix.