MISSOULA — A Montana man trying to catch the thieves who targeted his house pleaded not guilty Wednesday to deliberately killing a 17-year-old German exchange student who entered his garage, a case that ignited debate about laws allowing people to kill to protect their property.

Markus Kaarma, 29, of Missoula was arraigned in the April 27 death of Diren Dede of Hamburg, Germany, and prosecutors asked District Judge Ed McLean to increase Kaarma’s bond to $500,000. Deputy Missoula County Attorney Andrew Paul said Kaarma’s neighbors fear him and the investigation into the deadly shooting turned up a pattern of irrational and aggressive behavior.

Defense attorneys argued the neighbors’ fears are “not based in logic” but are a result of the public outcry over the case that caused some critics to question a Montana law that allows people to use lethal force to defend themselves or their property. 

McLean kept Kaarma’s bail at $30,000 after confirming the defendant surrendered his firearms. The judge asked Kaarma, who has posted bond, to turn over his passport.

Prosecutors allege Kaarma and his wife were frustrated over recent burglaries and set up motion sensors and video cameras to try to catch the thieves. The couple had left their garage door partially open the night of the shooting, and Kaarma blindly fired four shots into the garage after they spotted a trespasser, charging documents said. Dede was hit in the head and arm and died a short time later at the hospital.

Kaarma’s attorney, Paul Ryan, has said his client didn’t intend to kill Dede. 

“He was scared for his life,” Ryan said. Kaarma also has said he was defending his property.

Prosecutors say Dede was apparently looking for alcohol when he entered Kaarma’s garage.

Two other teens have been charged with stealing marijuana, wallets, credit cards and a cellphone from the garage and vehicles at Kaarma’s house in the weeks prior to the shooting.