In a rare move, both the prosecution and defense agreed the state’s Court of Appeals should overturn a man’s assault conviction because a Larimer County judge incorrectly instructed jurors about self-defense.

Consequently, a three-judge appellate panel on Thursday ordered a new trial for Anthony John Trimarco, who is currently serving a 12-year prison sentence.

In criminal cases where some credible evidence supports the notion that a defendant acted in self-defense, judges must give an instruction to jurors about how to apply the law of self-defense. The prosecution, in addition to proving the charged offense, must also prove beyond a reasonable doubt that the defendant was not defending himself at the time he committed the crime.

Two pairs of men had been out drinking in Loveland when they encountered each other on the street. From the testimony at trial, it was unclear who started the confrontation, but it ended with Trimarco stabbing a man from the other group with a knife. He maintained he was acting in self-defense, as the victim was wrestling with Trimarco on the ground at the time.

Prosecutors charged Trimarco with five offenses, including menacing, assault and attempted murder. Jurors only convicted him of one crime: first-degree assault.

At Trimarco’s 2020 trial, District Court Judge Juan G. Villaseñor agreed to instruct the jury that they could find Trimarco acted in self-defense. However, after telling jurors the prosecution had to prove beyond a reasonable doubt that Trimarco committed assault, he further explained “the prosecution does not have an additional burden to disprove self-defense.”

Trimarco appealed his conviction, claiming Villaseñor’s instruction was faulty. In an atypical instance of agreement on appeal, the Colorado Attorney General’s Office echoed that the conviction could not stand. The appellate panel concluded they were both correct.

“In our view, this instruction misstated the law,” wrote Judge Jaclyn Casey Brown in the March 16 ruling, “because the trial court must affirmatively instruct the jury that the prosecution bears the burden of proving beyond a reasonable doubt that the defendant did not act in self-defense.”

Because the constitutional guarantee of due process requires convictions be based on proof beyond a reasonable doubt for every element of a crime, including an assertion of self-defense, the Court of Appeals ordered a new trial for Trimarco on only the assault charge.