Police in Minnesota say a 15-year-old boy unintentionally fatally shot by his 13-year-old brother while playing "cops and robbers."

Police and paramedics responded to an Eagan home Sunday morning after the 15-year-old reported his brother was unresponsive and bleeding.

The 15-year-old told dispatchers his brother had fallen and stabbed himself while running with a knife. But when police arrived, the older boy told officers he had accidentally shot his brother.

The boys were home alone with their 11-year-old sister when they found an unloaded 9 mm pistol belonging to their father. Investigators say at some point, the firearm was loaded, then thought to be unloaded while the boys chased each other.

Police say the 15-year-old fired one round that struck his brother in the chest.

No one was arrested.