Prosecutors said a stranger was killed outside a grocery store moments after the attacker bought the knife inside.

PHOENIX — A Phoenix man was sentenced to 25 years in prison after a jury convicted him of second-degree murder in the stabbing death of a stranger outside a Safeway grocery store, prosecutors said.

The sentence closed a case that prosecutors described as both sudden and chillingly simple. They said 48-year-old Damian Mitchell bought a paring knife inside a Safeway store on Dec. 29, 2024, then used it moments later to stab 29-year-old Reminisce Biddle after the two men exchanged words as they passed each other outside. The case mattered because it turned on a short timeline, strong surveillance evidence and the apparent randomness of a fatal attack between strangers.

According to the Maricopa County Attorney’s Office and local reports, the encounter unfolded near 5th Avenue and Osborn Road. Mitchell was inside the Safeway shortly before the attack, where surveillance video later showed him buying a knife. Prosecutors said that after leaving the store, Mitchell and Biddle crossed paths outside and exchanged words. The public record has not laid out what was said, and there is no indication in the available reports that the two men knew each other. What happened next became the core of the prosecution’s case. Authorities said Mitchell turned around, followed Biddle behind a building and stabbed him once in the chest. Biddle then managed to get back into the store for help before collapsing. Officers responded to the stabbing and Biddle was taken to a hospital, where he later died from his injuries.

The prosecution’s evidence appears to have been unusually direct. Investigators said surveillance video connected Mitchell to the knife purchase and to the moments before the stabbing. The county attorney’s office said the weapon matched Biddle’s wound, giving prosecutors a clean line from purchase to attack. That kind of evidence often shortens the factual dispute in a case, and the reporting that followed the verdict suggests that happened here. By the time sentencing arrived in February 2026, the state had already convinced a jury that Mitchell was guilty of second-degree murder, a class one dangerous felony in Arizona. The public summaries of the case do not describe a detailed defense explanation for why the stabbing happened or why a single exchange of words escalated into lethal violence. They also do not indicate that Biddle was armed or that the killing grew out of any prior dispute.

The setting added to the shock. This was not a hidden attack in a remote place or a private argument inside a home. It happened outside a neighborhood grocery store in central Phoenix, the kind of setting people move through every day without expecting violence. Prosecutors emphasized that ordinariness in their account by noting how little separated the knife purchase from the stabbing itself. The state’s theory was not that Mitchell arrived with a weapon already prepared. It was that he acquired one during a routine shopping trip, then used it minutes later in a confrontation with a stranger. That compressed sequence likely helped the case stand out and made the surveillance footage more important, because it allowed prosecutors to show jurors how quickly the attack developed and how closely the murder weapon was tied to the defendant’s actions inside the store.

The legal process is now complete at the trial-court level. The Maricopa County Attorney’s Office announced that Mitchell had been convicted by a jury and sentenced to 25 years in prison. That sentence reflects the seriousness Arizona law assigns to a second-degree murder conviction involving a deadly weapon. The public reports available after sentencing did not mention a plea offer, post-trial motion or immediate appeal filing. They focused instead on the county attorney’s summary of the case and on the final prison term. Any future review would likely come through the normal appellate process, but no such challenge was described in the available accounts. For now, the judgment stands as the court’s final answer to a homicide prosecutors said began with a passing exchange and ended with a single fatal stab wound.

Biddle’s death also gave the case a stark human frame. He was 29 and, by every public account, had no known connection to Mitchell before the attack. The brevity of the encounter is one reason the case remained notable after sentencing. It offered no long feud, no elaborate scheme and no broad mystery for detectives to solve. Instead, it became a case about how fast a public encounter can become deadly and how video evidence can preserve nearly every crucial step. By sentencing, the state’s story had prevailed: Mitchell bought a knife, followed a stranger and killed him outside a grocery store.

Mitchell is now serving a 25-year prison sentence in Arizona. The next milestone would come only if he seeks appellate review of the conviction or sentence.

Author note: Last updated March 15, 2026.