Charlie Kirk, a prominent conservative activist who had been speaking about gun violence, was fatally shot Wednesday during an event at Utah Valley University, authorities said.

Witnesses and a court affidavit describe a brief exchange moments before the attack in which a student asked Kirk about transgender mass shooters and Kirk replied, "Too many." Immediately after the remark, a gunshot rang out and Kirk was struck in the neck. He later died of a single gunshot wound, according to authorities.

Police arrested 22-year-old Tyler Robinson in connection with the killing and recovered a rifle they say was used in the shooting. A court-filed affidavit said a roommate provided incriminating text messages and directed officers to where the rifle could be retrieved. Investigators have said bullets found in the rifle bore inscriptions that included anti-fascist slogans and references to internet memes.

Utah Governor Spencer Cox said the roommate, identified by officials as Lance Twiggs, was a romantic partner who he described as "a male transitioning to female" and that Twiggs had been "incredibly very cooperative" with investigators. The FBI is assisting the inquiry, and authorities said the roommate is cooperating but has not been accused of any wrongdoing in charging documents made public so far.

According to reporting and law enforcement documents, the student who posed the question that preceded the shooting, identified as 29-year-old Hunter Kozak of Utah Valley University, posted a video statement afterward to clarify the lines of questioning. Kozak said the point being raised was the relative rarity of politically left violence and said people pointed to the irony of the exchange given what followed.

Law enforcement sources and court filings also detail investigative steps that included collecting evidence from an apartment Robinson shared with the roommate. Authorities said social media and online payment app handles tied to Robinson and associates were reviewed as part of the probe. The affidavit and police statements did not offer a motive for the attack.

Kirk, a father of two who had been active on college campuses and in conservative media, leaves behind his wife, Erika Frantzve, and two young children. On a Turning Point USA livestream broadcast after the shooting, Erika Kirk said she would continue the organization's campus tours and hold its annual conference as planned, pledging to honor his memory.

The killing has intensified debate over how mass shootings are categorized and the role of a shooter's gender or gender identity in public discussion. National assessments vary because there is no single universally accepted definition of a "mass shooting." Federal law defines a "mass killing" as an incident in which three or more people are fatally wounded in a public setting, but datasets and news outlets often use different thresholds and may or may not include gang-related killings.

A 2023 report by the U.S. Secret Service National Threat Assessment Center found that among mass attackers from 2016 to 2020, about 96 percent were men, roughly 3 percent were women and about 1.67 percent were transgender. Experts caution that those figures can be difficult to interpret because records sometimes do not capture gender identity consistently, and estimates of the transgender population vary. Studies cited by public-health and demographic researchers generally place the percentage of U.S. adults who identify as transgender well under 1 percent.

Public reaction has been swift. Former President Donald Trump posted a message on his platform characterizing Kirk as someone who "understood the Heart of the Youth in the United States of America" and noting that Kirk "was loved and admired by ALL." Conservative politicians and commentators have pointed to the case to renew discussions about campus safety, political rhetoric, and how data about perpetrators is used in public debate. Some officials and analysts emphasized that trans people are more often victims than perpetrators of violence, and that drawing broad conclusions from individual cases can be misleading.

The shooting has also prompted renewed attention to several past attacks in which the perpetrators have been identified as transgender, incidents that have figured in public and political argument about links between gender identity and violence. Among examples cited in public discourse are the 2023 Nashville Covenant School shooting, in which the attacker was reported to be a transgender woman and was killed in the confrontation with police; the 2019 Highlands Ranch school shooting in Colorado; and other incidents that have been included in lists circulated by some politicians and commentators. Public-health researchers and civil-rights advocates say such lists must be interpreted cautiously because the underlying data are incomplete and incidents differ widely in motive, context and classification.

Authorities have not released a motive for the Utah Valley University shooting. Court filings and police statements referenced by media outlets say investigators are examining the suspect's social-media activity, online aliases and communications recovered from the residence. Local and federal agencies continue to process evidence and interview witnesses as part of the ongoing criminal investigation.

Kirk's wife said the family's immediate priority is their children and that they intend to continue the conservative organization's programming. Law enforcement officials said the probe remains active and that additional details would be released as they become available.

This story is developing.