Protesters interrupted a candlelight vigil at New York University for conservative activist Charlie Kirk on Sunday night, singing a song title that authorities say was etched on one of the unused bullet casings recovered in the shooting that killed Kirk last week.

The NYU College Republicans posted video on X that shows a crowd of demonstrators breaking into the Italian anti-fascist song "Bella Ciao," a phrase that federal and state officials said was written on an unfired cartridge found by investigators at the scene of the Utah shooting. The student group said some protesters also directed death threats at the club's president, Ryan Leonard; the group wrote on X that demonstrators "threatened to kill NYU College Republican Club president Ryan Leonard. They're not looking for peace." In footage shared by the organization, a guitar-playing protester can be heard telling Leonard, "I don't want your salvation. I want you to f---ing die. We're not going to give you a second chance, even when you beg for it." The College Republicans described the crowd as a "woke mob."

Kirk, 31, a conservative activist and ally of former President Donald Trump, was fatally shot while speaking to a crowd at Utah Valley University in Orem last Wednesday, authorities have said. Police allege the gunman fired a single round from a rooftop using a high-powered rifle; the suspected shooter, identified by authorities as 22-year-old Tyler Robinson, was arrested late Thursday and is being held in a Utah jail on suspicion of aggravated murder.

Officials have not publicly established a motive. Utah Gov. Spencer Cox said investigators found anti-fascist slogans written on two of the unused casings recovered at the scene, including one that read "Bella ciao" and another with the words "Hey, fascist! Catch!" Other casings were marked with symbols and phrases similar to those associated with online gaming culture, officials said.

Federal authorities have released surveillance images of a person of interest in the case and said DNA evidence collected at the scene has been matched to Robinson, FBI Director Kash Patel confirmed Monday. Patel also said investigators found a handwritten note at the suspect's family home that he described as stating an intention to target Kirk. "That note was written before the shooting," Patel said.

In comments to Fox News, FBI Deputy Director Dan Bongino said the suspect had shown signs of intent and that friends and family reported he had become more politically engaged. Local authorities have said Robinson has not been cooperating with investigators.

Robinson is expected to appear in court on Tuesday and could face capital murder charges, which in Utah can carry the death penalty. State officials have said details of any charging decisions will be handled by county prosecutors.

Kirk's death has prompted vigils and moments of silence across the country. Mourners gathered at New York University, where students held a memorial that stretched outside campus space, and a line of people formed outside the Kennedy Center in Washington for a vigil on Sunday. Professional sports teams and venues held moments of silence in the days after the shooting.

Authorities have cautioned against drawing immediate conclusions about motive from inscriptions on ammunition. Investigators are conducting forensic and digital probes, including reviewing surveillance footage, tracing the source of the bullets and examining the suspect's online activity. Officials have said some of the markings on the casings were from online communities and gaming imagery, while others bore anti-fascist language.

Robinson, who lived in Utah, has been described by some acquaintances in social media posts and local reports as a straight-A student raised in the Mormon faith by Republican parents. Officials said he had lived with a transgender partner; law enforcement has said the partner is cooperating with investigators and has not been linked to the shooting.

The NYU College Republicans' account of the vigil drew criticism and concern from campus leaders and others who called for safety and restraint. University officials did not immediately respond to requests for comment on reports of threats at the event. The college group's posts were among several accounts and videos circulating on social media that show tense interactions between students and outside demonstrators following the shooting.

As authorities continue their investigation, local and federal agencies said they are coordinating to process evidence and determine the full sequence of events. The FBI and the Utah County Sheriff's Office have urged anyone with information or additional footage to come forward as prosecutors review the case and consider formal charges.