Defense attorneys for Byron Smith, who was convicted of killing two teenage intruders in his Little Falls home, filed an appeal Monday with the Minnesota Supreme Court arguing that Smith's trial was riddled with mistakes from the original indictment, through the trial and right up to the prosecutor's closing arguments.

In a 51-page brief, attorneys said that a series of missteps in Smith's prosecution began with the way the case was presented to a grand jury four months after he shot 18-year-old Haile Kifer and 17-year-old Nick Brady, who broke into his home on Thanksgiving Day in 2012.

On top of that, they argued, the trial itself included a host of errors, including the judge prohibiting them from giving a complete defense, improperly closing the courtroom and failing to properly instruct the jury on a disputed claim made in closing arguments.

The attorneys are asking the high court to vacate Smith's conviction and either dismiss his first-degree murder indictment or send his case back to district court for a new trial.

"Make no mistake about it, [Smith] was not given a fair trial," defense attorney Steve Meshbesher said in an interview.

Prosecutor Peter Orput said in a phone interview Monday that he hadn't yet read the briefing, but he's confident that the Supreme Court will uphold the conviction.

Smith, 66, is serving a life sentence without the possibility of release after a jury took three hours last April to convict him of first-degree premeditated murder.

Prosecutors portrayed him as a vigilante who set a trap after a series of previous burglaries at his home, then waited in his basement and coldly executed the teenage cousins by continuing to shoot them after they no longer posed a threat.

Defense attorneys portrayed Smith as a genteel retired State Department employee who was scared to his core after being targeted by burglars who stole guns and other property in the prior break-ins.

An audio recording that Smith had set up often left the courtroom silent during the trial with sounds of gunshots booming, of the teenage cousins groaning and screaming, and then of Smith muttering how he saw them as "vermin" as they lay wrapped in tarps on his floor.

Grand jury issues

Defense attorneys argued in their filing that prosecutors improperly presented evidence in the grand jury hearing. Grand juries must indict defendants on first-degree murder charges.

The state tried to destroy the credibility of Smith's neighbor who was testifying, they wrote. Neighbor Bill Anderson testified that Smith contacted him a day after the shootings and asked for help in finding a lawyer. During questioning, prosecutor Orput indicated that Anderson had told police about Smith asking him to find a defense attorney, which Anderson said was not correct.

"The State manufactured the words 'defense lawyer' and 'criminal defense lawyer' out of thin air," the filing said. That wrongly inferred to the grand jury that Smith thought he'd committed a crime, the attorneys argued.

The state also elicited irrelevant testimony from the teens' mothers and improperly told the grand jury that Smith already had been charged with second-degree murder in the case, among other missteps, the filing contends.

Alleged trial missteps

Defense attorneys also repeated claims they made publicly after Smith's conviction: that they weren't allowed to present testimony from Brady's friends linking him to prior burglaries at Smith's property. Judge Douglas Anderson had ruled that efforts to link Brady to those prior burglaries were irrelevant because there was no evidence that Smith knew who Brady was or believed that it was Brady who had burglarized his home on prior occasions.Although the jury heard some evidence of the prior burglaries from other witnesses, defense attorneys argued in the filing that the testimony would have substantiated the "nature and circumstances of the previous break-ins at his home that bore directly on his [Smith's] state of mind … when he elected to use deadly force," the filing said.

They argued that they should have been able to present evidence of a shoe print match on a broken door panel from a previous break-in, which Smith had shown to police before Thanksgiving. After shooting Brady, the defense claims, Smith recognized that the tread print on Brady's shoes matched the one on the door panel, making Smith connect Brady to prior burglaries and making him afraid that the second person entering his home may have had his stolen firearms.

The attorneys also criticized the court for not allowing them to show the jury a gun that had been stolen from Smith's house. They also weren't allowed to present testimony from a former law enforcement officer and firearms instructor who was prepared to talk about "critical-incident stress, how it affects adrenaline and tunnel vision and auditory deprivation." That would have helped the jury better understand Smith's actions, they argued.

Also cited in the filing was the temporary closing of the courtroom before opening statements, during which Judge Anderson reiterated that he would not allow certain testimony about the prior burglaries. Anderson said he closed the courtroom for that ruling because there was a risk of it being published and jurors learning of it if they didn't follow their oaths to abstain from news coverage during the trial.

The Star Tribune has sought to file a brief criticizing the courtroom closure, saying the public and the press have significant interests in seeing that rules of access to criminal proceedings are followed. The newspaper does not intend to take a position on a proper remedy for the courtroom closure.

'I'm sorry' changed to 'unclear'

Questions over whether Kifer uttered the words "I'm sorry" during the shootings was at the heart of the defense's final appeal claim.

A transcript of the audio recording originally included her saying those words, but the court ordered it removed, saying the female voice on the audio did not say "I'm sorry." The transcript was changed to say "unclear."

But Orput, the prosecutor, mentioned it to the jury in his closing argument, and defense attorneys quickly asked for a mistrial. The judge declined and said the jury would be cautioned against considering those words. No such caution ever was given, the defense said.

Orput said in an interview that he hopes the appeal "will be the end of the story for these victims' families … We had a full and complete trial and the jury had no problem finding him guilty."

The issues raised in the appeal "in my opinion, are irrelevant as to whether or not Smith murdered those kids," Orput said.