A Montana legislator said Thursday she would seek to repeal the state's "castle doctrine" after a man accused of killing an unarmed German teenager said he will use the stand-your-ground law in his defense.

Markus Kaarma opened fire with a shotgun into his darkened garage in Missoula early Sunday, killing 17-year-old Diren Dede of Hamburg, police said. Kaarma, 29, a Forest Service firefighter, told police that he had seen a man in his garage while watching a video monitor. He was charged Monday with homicide.

Defense lawyers say they will invoke the state's castle doctrine, which allows use of force to defend against unlawful entry of a home, provided the person believes it necessary to stop an assault or prevent a forcible felony.

Montana Rep. Ellie Boldman Hill, a Democrat, said Dede's death has prompted her to draft legislation that will strip the law of those provisions. "It's not the American system of justice for a single individual to act as judge, jury and executioner," Hill said.