Byron Smith, who described the teens he killed as 'vermin', takes a break during the first day of his trial. Credit:AP The day after Mr Smith killed two teens who entered his home, he matter-of-factly described the shootings in chilling detail, telling authorities he finished off one teen with a shot under her chin because a .22-calibre "doesn't go through bone very well," according to an audio recording of a police interview played in court. The killings stunned this central Minnesota community and stirred debate about how far people can go to defend their homes. 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. The teens were not armed, but Mr Smith told authorities he assumed they were — and he thought they had taken guns from his house in a past burglary.

Nick Brady: killed with his cousin Haile Kifer, after breaking into a home in Little Falls, Minnesota. Credit:Facebook Assistant Washington County Attorney Brent Wartner told jurors that Smith thought a neighbour girl had been breaking into his home. On that day, he moved his truck away from his house, sat in his basement "and he waited", Mr Wartner said. "He's down in the basement, in a chair, tucked between two bookcases at the bottom of the stairs. He said he was down there reading a book ... with his Mini-14, a .22-calibre revolver, some energy bars and a bottle of water," Mr Wartner said. Haile Kifer was shot dead after entering Byron Smith's house on Thanksgiving, 2012. She was unarmed. Credit:Facebook Authorities who searched Mr Smith's home after the killings testified on Wednesday that they found an audio recorder that was turned on and an operating video surveillance system. The recorder was sitting on top of books on a bookshelf, near a chair where prosecutors say Mr Smith waited for the teens.

In the recording, Mr Smith can be heard breathing heavily and whispering. At one point, he said: "I don't see them as human. I see them as vermin." Mr Smith's home recording also captured the actual shootings, including Ms Kifer screaming after she was shot. Janet Nelson, a special agent with the Bureau of Criminal Apprehension, testified that the full recording was six hours and 24 minutes long. She condensed it into 29 minutes of highlights, enhancing volume in some areas, and cutting background noise in others. The tape was presented to jurors as a sequence of events, but defence attorneys raised questions about the recording on cross-examination, noting it had been spliced and altered, and some key pieces of information were left out. The recording presented in court apparently starts before the shootings, with Mr Smith talking about having someone come over and giving instructions on where to park. Mr Smith also is heard saying: "I realise I don't have an appointment, but I would like to see one of the lawyers here." The next sound played in court was the sound of glass shattering, followed by footsteps and heavy breathing. The recorder captured the sounds of Mr Smith shooting Mr Brady as he came down the stairs, including a groan from Mr Brady after the first shot. A total of three shots were fired, and Mr Smith can be heard saying "You're dead."

The criminal complaint says Mr Smith then placed Mr Brady's body on a tarp and dragged it into another room, then sat down and reloaded his weapon. Ms Kifer then comes down the stairs. More shots are fired, and Ms Kifer screams. Then Mr Smith said: "You're dying" and called her "b----" twice. Another shot was heard soon after. In a statement to investigators, Mr Smith called it a "finishing shot." Then, Smith whispers: "I'm safe now," according to the recording. Ms Nelson said for the next several hours, Smith can be heard talking to himself, often in whispers. He is heard repeating the request for someone to come to his house, and repeating the parking directions he apparently recited before the shootings.

He also said: "I was doing my civic duty ... I had to do it." And he said the girl "was going to go through her life spoiling things for other people." In the police interview recordings, Mr Smith can be heard politely recounting details to investigators. As the recordings were played on Monday, Mr Smith sat still at the defence table, at some points crying. He said he didn't call police because the teens were already dead and "just cause my Thanksgiving is screwed up I don't need to screw up yours." The next day, he asked a neighbour to call police. Mr Smith is a retired security engineer for the US Department of State.

Ms Kifer and Mr Brady were cousins. The two were well-known in the community, and both were involved in sports. Court documents from another case show Mr Brady had burgled Smith's property at least twice in the months before he was killed. AP