Under Minnesota law, a person may use deadly force to prevent a felony from taking place in one's home or dwelling, but authorities have said Smith crossed a line when he continued to shoot the teens after they were no longer a threat.
Smith's attorney, Steve Meshbesher, said the evidence will show his client is innocent of the accusations against him. Prosecutor Pete Orput said he is looking forward to letting jurors decide whether Smith's actions were premeditated.
Messages left with family members of the victims were not returned.
According the complaint, Smith told authorities he was in his basement that Thanksgiving Day when he heard a window break upstairs and heard footsteps in his house. He saw Brady coming down the basement stairwell, then shot him. Brady fell. And as Brady was looking up at Smith, Smith shot him the face, the complaint said.
The complaint said Smith told an investigator: "I want him dead."
Smith said he dragged Brady's body into his workshop, then sat in a chair. When Kifer came down the stairs, he shot her too. After she fell, he tried to shoot her again but his gun jammed, and she laughed, the complaint said. Smith pulled out another gun and shot her several times in the chest, acknowledging he fired "more shots than I needed to," the complaint said.
He allegedly dragged her into the room with Brady. Kifer was still gasping for air, so he fired what he called a "good, clean finishing shot" under her chin "up into the cranium," the complaint said.
Smith is a retired security engineer for the U.S. Department of State. His job would have focused on technical security issues for U.S. embassies, such as building layout and alarms.
Meshbesher, Smith's attorney, has said Smith's home had been broken into a half-dozen times in the months before the shootings, and he installed a security system to protect himself.