Minnesota father sentenced to maximum 6 months in prison for unsecured gun that young son used to kill younger brother

At the time of the shooting, Mammenga was in a pickup truck with two boys and their mother, who was in a relationship with Mammenga. A deputy found the pickup truck outside Fairmont and stopped it. Mammenga got out of the vehicle, holding Matthew, who had been shot in the head.

Mammenga performed CPR before an ambulance arrived and took over. He told officers the 4-year-old accidentally shot Matthew while the truck was in motion and the gun was still in the older child’s backseat. The injured boy was taken by air ambulance to a Rochester hospital, where he died two days later.

According to court documents filed by the Sheriff’s Office, law enforcement officers also seized three rifles from the truck along with ammunition and magazines for those weapons.

The 4-year-old told a sheriff’s deputy that he grabbed the gun from the front seat when the boys were left alone in the truck while Mammenga and his mother went inside to grab something. Mammenga told police he left the gun in the passenger door pocket before getting inside.