A St. Louis man killed his two sons before turning the gun on himself on Saturday.

St. Louis County Police issued an Amber Alert for two children believed to have been abducted by their father, 43 year old Christopher Cadenbach.

Cadenbach spent Saturday with his two children, Ethan Cadenbach, 5, and Owen Cadenbach, 4. He reportedly made stops to see his estranged wife and mother earlier in the afternoon.

Cadenbach's mother contacted police after he began exhibiting strange behavior, using phrases such as "not being taken alive." Cadenbach also made references to suicide by cop. A $100,000 domestic violence warrant had been issued for his arrest. The Amber Alert was issued around 6:30 p.m., in the St. Louis area.

Cadenbach's vehicle was spotted around 8 p.m. by a Cliff Cave Park Ranger. Police arrived on scene and approached Cadenbach and the children. As they approached, Cadenbach shot and killed his children before turning the gun on himself.

The investigation is currently ongoing.