Colorado’s second-highest court reversed a defendant’s convictions for murder and assault last week after concluding a Denver judge incorrectly omitted key jury instructions that could have affected the verdict and sentencing.

Stephen C. Swainson fatally stabbed Israel Casillas in downtown Denver one night in September 2020. He also stabbed Levi Casillas, Israel’s brother, who survived. Although Swainson and Levi Casillas testified about a physical confrontation, Swainson said that Israel Casillas assaulted him on the street, with Levi Casillas and a third man jumping in to hit and kick Swainson.

Consequently, Swainson asserted that he pulled out his knife and started swinging to defend himself.

Levi Casillas, in contrast, testified that he saw his brother and Swainson fighting and ran to assist.

District Court Judge Kandace C. Gerdes agreed to instruct the jury that, under Colorado law, Swainson was entitled to use deadly force to defend himself if he reasonably believed he was in imminent danger of being killed or receiving “serious bodily injury.”

However, she declined to instruct jurors that Swainson could also legitimately use deadly force if he believed his assailants would cause him “bodily injury” with a deadly weapon. Gerdes also did not ask jurors to decide whether Swainson acted upon “a sudden heat of passion.” Although a finding that Swainson stabbed the victims in the heat of passion would not have resulted in an acquittal, it would have reduced the severity of the murder and assault charges.

Jurors found Swainson guilty of second-degree murder, attempted murder, and assault. He received a sentence of 96 years for murder and 64 years for the other offenses.

On appeal, Swainson argued jurors should have considered the entirety of his self-defense instruction, as well as whether he was provoked into acting in a heat of passion.

“If being physically attacked by three drunk people — while alone, at night — isn’t highly provoking, what is? The State offers no explanation, and there’s none,” wrote public defender Emily Hessler. “A physical attack is the prototypical example of a highly provoking act justifying a heat of passion instruction.”

The government responded that there was a “dearth of evidence” that Swainson acted in a heat of passion. Further, there was no evidence that Swainson “was injured at all,” so it did not matter that jurors never considered whether Swainson reasonably believed the victims would cause him bodily injury.

“Didn’t Mr. Swainson’s testimony show that the trio was intending to cause bodily injury to him by kicking him and beating him up with their fists? What was missing?” asked Judge Lino S. Lipinsky de Orlov during oral arguments to the three-judge Court of Appeals panel. “They’re kicking him in the head.”

Ultimately, the panel agreed that jurors should have received the missing instructions.

As for the self-defense instruction about Swainson’s right to use deadly force if he expected the victims would inflict bodily injury using deadly weapons — meaning their fists and feet — Lipinsky wrote that Swainson’s testimony could have established an entitlement to defend himself.

Even if jurors did not believe Swainson reasonably believed he was facing serious bodily injury or death, “the jury could have concluded from the evidence that Swainson was justified in using deadly physical force against the trio because he reasonably believed that they were committing or about to commit second degree assault,” which only requires bodily injury, wrote Lipinsky in the Aug. 20 opinion.

The panel also agreed that jurors should have evaluated whether Swainson acted in a heat of passion.

“Given the evidence that Swainson faced multiple assailants, was on the ground when the trio kicked him, lacked clear vision, and was involved in a continuous altercation, Swainson was placed in a vulnerable position,” Lipinsky wrote. “Viewing this evidence in the light most favorable to Swainson, we conclude that his vulnerability would excite an irresistible passion in a reasonable person.”

The panel ordered a new trial.

The case is People v. Swainson.