MINNEAPOLIS (WCCO) — The Little Falls man serving two life sentences without parole for killing two teenage burglars has just had his final appeal denied.

The United States Supreme Court issued its decision Monday on Byron Smith, who killed cousins Nicholas Brady, 17, and Haile Kifer, 18, on Thanksgiving of 2012 as they broke into his home. Smith claimed self-defense, but a jury disagreed and convicted him on two counts of first-degree premeditated murder.

READ MORE: Byron Smith’s Best Friend: ‘All He Wanted Was Peace & Quiet’

Smith argued he was denied his constitutional right to a public trial because the court was closed off to spectators and the media for a short time before opening statements. The Supreme Court disagreed.

Byron Smith (credit: CBS)

Smith claimed he used reasonable force in defending his home after being the victim of multiple break-ins. But prosecutors said he went beyond Minnesota’s “castle doctrine” law in his use of deadly force. Audio played during Smith’s trial, which he recorded in his home during the killings, revealed that he sat armed in his basement, waiting for the teens to enter. He then mocked them after he shot them, and continued to shoot them beyond the point where they posed a threat to his safety.

READ MORE: ‘Castle Doctrine’ Supporter: Smith’s Actions Go Beyond Protection

Smith is serving out his sentences at the Oak Park Heights correctional facility.