LITTLE FALLS, Minn. – A Minnesota homeowner who shot and killed two unarmed teenagers during a break-in was quickly convicted of premeditated murder Tuesday, with a jury taking about three hours to reject his claim of self-defense.

Byron Smith, a 65-year-old retiree who once set up security in American embassies for the U.S. State Department, shot Nick Brady, 17, and Haile Kifer, 18, multiple times after they broke into his home on Thanksgiving Day 2012.

Smith’s attorney said he was fearful after previous burglaries and presumed the intruders were armed. But prosecutors argued that Smith lay in wait in his basement and intended to kill the teens, with a setup so elaborate that lead prosecutor Pete Orput compared it to a deer stand. Their key evidence was an audio recording that captured the killings in chilling detail, including Smith’s taunts as the teens died.

The mothers of the teens, who were cousins, cried as the verdicts were read: Guilty on two counts each of first-degree and second-degree murder. Smith, who showed no emotion as he heard the verdicts, was immediately sentenced to life without parole. Defense attorney Steve Meshbesher said he would appeal.

Brady’s grandmother, Bonnie Schaeffel, was among family members who addressed the court after the verdicts.

She said Smith seemed like a “sour, angry old recluse who felt he was above the law.” She added she was sorry his house was burglarized, but said Kifer and Brady should have had the chance to grow up and learn from their mistake.

Kifer’s aunt, Laurie Skipper, read a statement from her niece’s parents: “Byron Smith made a conscious choice to shoot and kill our beautiful daughter Haile. The feelings of helplessness are overwhelming.”

Smith’s brother, Bruce, walked past reporters afterward without comment.

The teens’ killings stirred debate around the state and in Little Falls – a Mississippi River city of 8,000 about 100 miles northwest of the Twin Cities – 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. Prosecutors say Smith moved his truck to make it look like no one was home, and then settled into a basement chair 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, and had 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, Brady descending the basement stairs and Smith shooting Brady three times. 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 as Kifer screams. Smith says, “You’re dying,” followed soon by the sound of another gunshot, which investigators said Smith described as “a good, clean finishing shot.”

Later on the recording, Smith refers to the teens as “vermin.” Smith waited a full day before asking a neighbor to call police.

Smith did not testify. Meshbesher highlighted previous burglaries on Smith’s property, including one on Oct. 27 that included the theft of weapons. He said Smith was fearful, and had asked authorities to do a more thorough investigation.

During closing arguments, Meshbesher said his client was a victim, and the teens would still be alive if they hadn’t broken into Smith’s house. But Orput said Tuesday that Smith intended to kill, making a choice every time he pulled the trigger.

“We know what fear feels like,” Orput said. “Was it fear that drove this or was it something else?”

Kifer was a senior who was active in athletics at Little Falls High School. Brady was a junior and had wrestled at Little Falls High School before transferring to nearby Pillager High School.

Judge Douglas Anderson excluded evidence about the teens’ histories from the trial, including court documents that showed Brady had broken into Smith’s house and garage before. Brady and Kifer were also linked to another burglary; stolen prescription drugs were found in the car they were driving.

Meshbesher said the jury did not see all the evidence – an issue he will raise on appeal.

Orput said after the verdict that this wasn’t a case about self-protection, but rather a “senseless, sad, premeditated murder of two kids.”