Markus Kaarma, 30, (left in photo) is charged with deliberate homicide in the April 27 killing of 17-year-old Diren Dede from Hamburg.

Authorities said Dede was killed while "garage hopping" in Missoula last April in a possible search for alcohol. On the night of the shooting, Dede and another student approached the open door. Dede went inside while his friend stayed on the street.

Motion sensors and a video monitor alerted Kaarma. He waited 23 seconds after seeing an intruder in his darkened garage before taking his shotgun, followed by his common law wife, Janelle Pflager, carrying a baseball bat.

In opening arguments, Missoula County prosecutor Jennifer Clark said Kaarma "trapped him in the garage."

"At that point he became the aggressor," she said. "You can use deadly force in an occupied structure if there is a threat of violence, but you cannot be the aggressor." Clark said Kaarma lured Dede into his garage by leaving the door partially open and a purse inside.

Clark said Kaarma gave no warning before firing into the darkened garage and paused between the third and fourth shots. Dede was killed.

Emergency call

On the second day of the trial, the court listened to the emergency call Pflager made the night of the shooting. She was heard to say that Dede was bleeding from "everywhere" and lying face down "barely breathing" after Kaarma shot him.

Pflager said Kaarma didn't help her as she tried to help Dede, and he died a short time later at a Missoula hospital.

Defense attorney Paul Ryan countered that Kaarma, a former US Forest Service firefighter, acted in self-defense, fearing for the safety of his family.

"Castle doctrine"

Kaarma has pleaded not guilty and is expected to invoke Montana's so-called "castle doctrine" self-defense law, echoing the expression "my home is my castle." It allows for deadly force against a home invasion, if someone reasonably believes it is necessary to prevent an assault.

The doctrine was invoked in the 2012 shooting of an unarmed Florida teenager, Trayvon Martin, by a neighborhood watch volunteer who was following the 17-year-old. George Zimmerman was acquitted after arguing self-defense.

Ryan blamed lack of police response and growing anxiety from two previous burglaries for his client's volatile behavior. He also said that Dede was part of a larger high school burglary ring.

The German government is closely following the case and has condemned the killing as out of proportion to any risk to Kaarma.

jm/av (AP, AFP)