A Montana jury convicted Markus Kaarma, 30, of deliberate homicide in the case that caused an outcry in Germany and brought scrutiny to the state's law allowing the use of deadly force in some situations to protect home and family.
Kaarma shot 17-year-old Diren Dede, who was unarmed, in April after he was alerted by motion sensors in his garage. Witnesses testified that Kaarma fired four times at the teen.
He and his wife attended the entire trial, and he returned from Germany for the hearing.
Kaarma sat staring down during the proceedings, occasionally glancing around the crowded courtroom. He had buzz-cut dark hair and wore an orange jail suit.
"I'm sorry my actions caused the death of Mr. Dede," he told the judge.
Judge Ed McLean heard testimony from several people before handing down the sentence, including Kaarma's girlfriend, his mother, a detective, the teen's host parents and others.
Prosecutors argued Kaarma was intent on luring an intruder into his garage after it had had been burglarized at least once in the weeks before the shooting. Three witnesses testified they had heard Kaarma say he'd been waiting up nights to shoot an intruder.
Lead detective Guy Baker testified that the first three shots were low and seemed to follow Dede as he moved across the garage. But the fourth shot was aimed higher and struck Dede in the head, Baker said.
Kaarma's lawyers argued that their client feared for his life, didn't know if the intruder was armed, and was on edge because of a previous burglary.
The self-defense principle is a centuries-old premise that a person has the right to defend their home against attack. More than 30 states, including Montana, have laws expanding the right of people to use deadly force to protect their homes or themselves, some known as "stand your ground" laws.
His parents, Celal and Gulcin Dede, testified in December that they were unable to work or plan for the future after their son's death.
