A game of "cops and robbers" ended in tragedy at a Minnesota home on Sunday.

Police reported that 13- and 15-year-old boys found their father's gun while alone with their 11-year-old sister.  The 13-year-old was accidentally shot and killed.

The 9mm pistol was hidden and unloaded in the Eagan home when the boys found it. It is unclear who loaded the weapon, but police said that magazines for the gun were nearby.

The boys began chasing each other around the home, playing cops and robbers, and at some point the older son fired one round at his brother. the teen was struck in the chest, and died at the scene. Their sister did not witness the shooting, and was unhurt.

The 15-year-old called 911, and reported that his brother had fallen while running with a knife. He told the dispatcher that the boy was unconscious and bleeding, and police and paramedics were sent to the scene. When officers arrived, he admitted that he shot his brother.

Police said the tragedy "appears to be a horrible accident," and do not expect charges to be filed. The case will be presented to the Dakota County Attorney's Office for review. 

KidsHealth recommends keeping guns in a locked location, and storing ammunition separately, to decrease the chances of children accessing them. 

Earlier this month, a 15-year-old girl shot her 16-year-old brother after he allegedly beat her and locked her in a room.

The girl escaped the bedroom with the help of her younger sister, broke into their parents' room, and retrieved their 9mm handgun. She shot her brother once, killing him. The two sisters have been charged with murder.