A coroner's inquest jury found the officer involved shooting of a 15 year old boy was justified.

Tanner Chamberlain was holding a knife to his mother's throat. Taser cam video shows him dropping to the ground after being shot in the head within a minute after officer's arrived on scene.

Officer Derek Colling testified he took that fatal aim to protect Tanner's mother, even though a Metro Sergeant and Colling's own partner testified they were aware the boy was mentally challenged. 911 callers had warned he was bipolar and his mother begged officers not to shoot.

"He didn't want to die oh my god that bullet went right into his head. Oh my god, oh my god," explained Tanner's mom Evie Oquendo.

"I could hear the white female say, don't shoot him, don't shoot him, but he had a knife to her neck and I believe he was going to kill her," testified Officer Colling.

Officers testified they couldn't get a clear shot with a taser because of the way Tanner was holding his mom and lethal force was used when he didn't drop the knife.