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A man who shot and killed a German exchange student caught trespassing in his garage was convicted of deliberate homicide in a case that attracted attention as a test of "stand your ground" laws in the U.S. that govern the use of deadly force against attackers.

Cheers erupted in the packed courtroom when the verdict was read Wednesday in the case against Markus Kaarma, 30. The case generated outcry in Germany, where a Hamburg prosecutor said this week his office was conducting its own investigation.

Kaarma shot 17-year-old high school student Diren Dede in the early hours of April 27 after being alerted to an intruder by motion sensors. Witnesses testified Kaarma fired four shotgun blasts at Dede, who was unarmed.

The teen's parents were in the courtroom and hugged and cried at the outcome, while others applauded.

"It is very good," said Dede's father, Celal Dede, with tears in his eyes. "Long live justice."

Kaarma remained stoic as he was taken into custody at the end of the hearing. He faces a minimum penalty of 10 years in prison when he is sentenced Feb. 11. His lawyers plan to appeal.

Dede's parents attended the entire trial, often leaving the crowded courtroom during emotional testimony. The Hamburg teen was studying at Missoula's Big Sky High School and was to leave the U.S. after the school term ended in just a few weeks.

Kaarma's attorneys argued at trial that he feared for his life, didn't know if the intruder was armed, and was on edge because his garage was burglarized at least once in the weeks before the shooting. They said Kaarma's actions were justifiable because he feared for his family's safety.

More than 30 U.S. states, including Montana, have laws expanding the right of people to use deadly force to protect their homes or themselves, some of them known as "stand your ground" laws. The self-defence principle is known as the "castle doctrine," a centuries-old premise that a person has the right to defend their home against attack. The name evokes the old saying, "my home is my castle."

Montana's law was amended in 2009 to state that a person who is threatened with physical harm has no duty to retreat or summon law enforcement assistance prior to using force.

Prosecutors argued Kaarma was intent on luring an intruder into his garage and then harming that person. That night, Kaarma left his garage door partially open with a purse inside. Three witnesses testified they heard Kaarma say his house had been burglarized and he'd been waiting up nights to shoot an intruder.