A 5-year-old boy in Elmo, Missouri, accidentally shot and killed his 9-month-old brother Monday, WDAF-TV reports.

Police said the boys' mother, Alexis Wiederholt, called 911 Monday morning and told dispatchers that the older boy had shot the baby with a paintball gun. However, officers said the infant had actually been shot with a .22-caliber Magnum revolver. The baby was taken to the hospital and pronounced dead.

The loaded gun had been stored on a shelf in the headboard of Wiederholt's bed, according to Nodaway County Sheriff Darren White.

Neighbor Kathy Armentrout said four boys, including the baby and 5-year-old, live in the home.