A Montana homeowner was found guilty of deliberate homicide by a jury on Wednesday in the shooting death of a German high school exchange student who broke into his garage.

Witnesses said that Markus Kaarma admitted that he planned to shoot the kids he suspected were burglarizing homes in his neighborhood, reports Reuters. In order to lure an intruder, he left his garage door partially open and placed a purse with cash inside, prosecutors said. He also placed a motion detector and baby monitor in the garage.

On April 27, 17-year-old Diren Dede took the bait and entered Kaarma's garage. That's when Kaarma went outside and fired four blasts with a shotgun into the garage, fatally shooting the student in the head.

Defense attorneys argued that Kaarma's actions were protected under the state's version of a "castle doctrine" self-defense law, which allows someone to use deadly force when necessary in order to protect their home and family. They also said he feared for his life and didn't know if the intruder was armed.

However, prosecutors described the 30-year-old former U.S. Forest Service firefighter as an armed aggressor who purposely lured a non-violent burglar to his death.

In addition, prosecutors cast doubt on the argument that Kaarma believed he was in danger, and noted ballistic evidence that showed Kaarma had repositioned himself for a final kill shot after the unarmed teen was already wounded.

During the trial, hair stylist Tanya Colby testified that Kaarma told her:

"I've been up three nights with a shotgun waiting to kill some kids," Colby said Kaarma said according to the Associated Press.

Colby added that later Kaarma told her, "I'm not kidding, you're seriously going to see this on the news."

The victim's father, Celal Dede, applauded the decision.

"We are very happy -- long live justice," he said.

Kaarma could be sentenced to 10 to 100 years in prison on Feb. 11.