Utah Gov. Spencer Cox said Sunday that authorities believe the suspect accused of killing Turning Point USA founder Charlie Kirk embraced a "leftist ideology" after appearing to become increasingly radicalized in recent years, but officials have not yet established a motive.
Cox spoke about 22-year-old Tyler Robinson in interviews and at a news conference as investigators continued to piece together evidence in the shooting that authorities say occurred Wednesday at a Turning Point USA event at Utah Valley University in Orem. Robinson is being held in Utah County and has not been cooperating with authorities, Cox said; officials have placed him on "special watch" pending the completion of a mental health evaluation.
Cox told NBC's "Meet the Press" that family and friends described Robinson as a "very normal young man" who changed politically after leaving Utah State University and moving back to southern Utah. The governor said acquaintances reported increased involvement in gaming and activity on "dark places of the internet," including Reddit communities, which he said may have played a role in Robinson's apparent shift.
Investigators cited markings on ammunition used in the shooting as a piece of the evidence they are examining. Cox referenced records showing at least one bullet casing bore the message, "Hey, fascist! Catch!" Cox said that detail underscores the "memeification" of political violence in the current online environment.
Robinson was arrested following the attack that killed Kirk, who was identified in news reporting as a husband and father of two. Authorities have said they expect to file charges against Robinson on Tuesday, though Cox and law enforcement officials said that until the mental health evaluation is complete some investigative work and disclosure of information will remain limited.
Senior-level FBI officials confirmed to media outlets that Robinson had been in a romantic relationship with a transgender partner who is reported to be transitioning from male to female. Cox said the partner has been cooperative with authorities. Officials from the Utah County Sheriff's Department said Robinson has not confessed and has declined to cooperate with investigators since his arrest.
The department said Robinson is being kept under a heightened watch while the mental health assessment proceeds. Officials did not provide additional details about the evaluation or its expected duration but said the step is standard procedure when questions about a suspect's mental state arise.
Law enforcement agencies, including the FBI, are investigating multiple leads in the case. Some reporting indicated federal investigators were looking into whether any left-leaning groups or networks had ties to Robinson; authorities have not publicly confirmed any organizational links and said the probe remains ongoing.
Cox said authorities were interviewing people in Robinson's life to reconstruct a timeline and understand influences that could explain how his views may have changed. He emphasized the importance of answering broader questions about radicalization and online communities while avoiding premature conclusions about motive.
A memorial for Charlie Kirk was visible on the Utah Valley University campus on Saturday, and the shooting has prompted responses from political leaders and campus officials calling for calm and cooperation with investigators. Officials have urged the public to allow law enforcement to complete interviews and forensic work before drawing conclusions about motive or affiliations.
The investigation remains active. Law enforcement officials said more information, including formal charges, could be released when Robinson appears in court or when the mental health evaluation is concluded and prosecutors decide on specific counts to file.