Charges will not be filed against a Broseley, Missouri, teenager who shot and killed his mother’s live-in boyfriend as the man allegedly was holding a knife to her throat and threatening to kill her.

Authorities said Brody Carter’s actions in killing Thomas Sherrion were “third-party self-defense.”

The 41-year-old was killed Sunday evening at the County Road 625 home he shared with Carter and the teen’s 55-year-old mother, Connie Diel.

Butler County, Missouri, investigator Wes Popp described the events leading up to the shooting as the “same ol’ domestic violence (where) the two are fighting.”

Sherrion and Diel, who had been “together” about 12 to 18 months, had an “on and off relationship that started as verbal altercations and went into the physical,” Popp said.

The couple had been arguing on and off for more than a day leading up to the incident.

On Saturday, Sherrion and Diel “started arguing about noon,” Popp said. “They began arguing again where physical threats had been made.”

The apparent issue just before the shooting involved Sherrion being angry at Diel for being on Facebook.

“He starts threatening to pick her up and throw her out the living room window (and) to bite her face off,” Popp said. “The son is hearing this again and goes back to the doorway.

“From there, you can see the chair Tom is sitting in.”

Popp said Sherrion wore a military-style knife on his belt.

“Brody sees Tom all of a sudden jump up and pull the knife out and run toward his mother,” Popp said.

“Brody runs inside his bedroom and grabs his rifle, thinking Tom is going to hurt his mom.”

Popp said Carter came out of his bedroom to the entrance into the living room and “sees Tom holding a knife against his mother’s neck. He fires one round at Thomas, hitting him in the back. Tom ends up dead in the floor.”

After firing the shot, Carter dialed 911 on his cellphone and handed it to his mother while he began “applying pressure to Tom’s wound until EMS and law enforcement arrived,” Popp said.

Sherrion was taken to Poplar Bluff Regional Medical Center, where an emergency-room doctor pronounced him dead at 10:10 p.m., according to Butler County Coroner Jim Akers.

When deputies arrived at the scene, Popp said, mother and son were split up and taken to the sheriff’s department, where they were interviewed separately.

Diel reportedly told officers Sherrion had “done things like this in the past, but tonight he meant it.”

Diel told officers Sherrion had threatened to kill his mother while holding the knife to her throat.

Once the scene was completed, Popp said, he and a crime-scene investigator discussed the findings, which “matched perfectly” with the statements of mother and son.

Pertinent address:

Broseley, Mo.