A Minnesota homeowner who shot and killed two teenagers during a break-in was convicted Tuesday of premeditated murder.

Bryon Smith had claimed he was simply defending himself during the break-in at his home in the small city of Little Falls on Thanksgiving Day 2012. Smith's attorney said the 65-year-old was fearful after previous burglaries.

But prosecutors argued that Smith waited in his basement and intended to kill the teens. A total of nine shots were fired at 17-year-old Nick Brady and 18-year-old Haile Kifer.

Jurors began deliberating Tuesday morning and within three hours had a verdict: Guilty on two counts each of first-degree and second-degree murder. Mothers of the teens cried as the verdicts were read, while Smith showed no emotion. Defense attorney Steve Meshbesher said he would appeal.

The teens' killings stirred debate around the state and in Little Falls -- a Mississippi River city of 8,000 about 100 miles northwest of Minneapolis -- about how far a homeowner can go in responding to a threat. Minnesota law allows deadly force to prevent a felony from taking place in one's home or dwelling, but one's actions must be considered reasonable under the circumstances.

Prosecutors said Smith's plan was set in motion on the morning of the killings, after Smith saw a neighbor whom he believed responsible for prior burglaries drive by. Prosecutors say Smith moved his truck to make it look like no one was home, and then settled into a chair in his basement with a book, energy bars, a bottle of water and two guns.

Smith also set up a hand-held recorder on a bookshelf, which captured audio of the shootings -- key evidence in the prosecution's case. Smith had also installed a surveillance system that recorded images of Brady trying to enter the house.

The audio, which was played several times in court, captured the sound of glass shattering, then the sounds of Smith shooting Brady three times as he descended the basement stairs. Smith can be heard saying, "You're dead." Prosecutors said Smith put Brady's body on a tarp and dragged him into another room, then sat down, reloaded his weapon and waited.

About 10 minutes later, Kifer came downstairs. More shots are heard on the recording, then Kifer's screams, with Smith saying, "You're dying." It's followed soon after by another shot, which investigators said Smith described as "a good, clean finishing shot."

The teens were unarmed, but Smith's attorneys had said he feared they had a weapon.

The tape continued to run, and Smith was heard referring to the teens as "vermin." Smith waited a full day before asking a neighbor to call police.

Smith did not testify on his own behalf. Meshbesher highlighted previous burglaries on Smith's property, including one on Oct. 27 that included the theft of weapons. A neighbor testified that Smith came to his door after that burglary and appeared very frightened. Meshbesher said Smith wrote a memo to the Morrison County Sheriff's Office on Oct. 29 asking them to investigate.

Meshbesher said in his closing arguments that the teens would still be alive if they hadn't broken into Smith's house. He also said Smith had a legal right to use deadly force to defend himself.

Before retiring from the U.S. State Department, Smith worked on technical security issues for American embassies, such as building layout and alarms.

Kifer was a senior who was active in athletics at Little Falls High School. Brady was a student and a wrestler at that school before transferring to nearby Pillager High School, where he was a junior. They were cousins.

Court documents that were not allowed as evidence showed Brady had broken into Smith's house and garage before. Brady and Kifer were also linked to another burglary the day before they were killed; stolen prescription drugs were found in the car they were driving.

Judge Douglas Anderson excluded evidence about the teens' histories from the trial as irrelevant