Yoni Barrios was born in 1990 in Guatemala. His early life in his home country has not been widely documented, but available records show that he eventually made his way to the United States. Immigration officials believe Barrios entered the country illegally, without passing through an official border checkpoint. This placed him in the precarious position of living in the United States without legal documentation or stable support.

Prior to the Las Vegas attack, Barrios had a troubled past. In 2019, he was charged with domestic violence in California. However, the case never moved forward in the court system due to pandemic-related delays and the victim’s failure to appear in court. Despite this incident, Barrios did not have a lengthy criminal record in the U.S..

When Barrios came to Las Vegas in 2022, he had little financial security and reportedly displayed erratic behavior. He expressed interest in returning to Guatemala and even asked a janitor at the Wynn Casino to contact immigration officials on his behalf. He was also observed telling hotel security guards that he wanted to sell his knives.

On October 6, 2022, shortly before 11:40 a.m., Barrios approached a group of four showgirl impersonators outside the Wynn Casino along the Las Vegas Strip. He allegedly told them that he was a chef at the Wynn and asked if he could take a photo with them for free. When they declined, he became agitated. According to later police reports, Barrios believed the women were mocking him and making fun of his clothing. Fueled by anger and paranoia, he suddenly stabbed two of the women without warning.

Barrios then ran along the Las Vegas Strip, continuing his rampage. Over the course of a short but brutal spree, he attacked six additional victims, both tourists and locals, in a series of random and unprovoked assaults. Witnesses described scenes of chaos as bystanders attempted to help the wounded and others fled in panic.

Two of the stabbing victims ultimately died, making the attack the deadliest stabbing incident in the United States since 2020. Six others sustained injuries, ranging from critical to moderate, but survived after being rushed to area hospitals.

As Barrios fled, several witnesses pursued him. Police quickly arrived and arrested him nearby, identifying him by his bloodstained chef’s jacket. A knife believed to be the murder weapon was later recovered from bushes where he had thrown it during his retreat.

Following his arrest, Barrios reportedly admitted to police that he committed the attacks to “let the anger out.” 

In the weeks following, Barrios’s case moved into the courts. At his initial arraignment, his public defender raised concerns about his mental health. In December 2022, two court-appointed psychiatrists evaluated him and concluded that Barrios was mentally unfit to stand trial, unable to comprehend the proceedings or the charges against him. A Nevada court subsequently ordered his indefinite placement at a state psychiatric facility until such a time he might be found competent to face justice.