Utah. Less than two weeks before Charlie Kirk’s assassination in Utah, law enforcement in central California conducted three days of reconnaissance to prepare for a speech by the conservative activist at a local church in politically friendly territory.

Officials researched potential escape routes and identified local activists opposed to Kirk. On the day of the indoor event in Visalia, which drew 2,000 attendees, around 60 law enforcement officers monitored Kirk’s movements to and from the church, deploying a drone to secure surrounding rooftops, Tulare County Sheriff Mike Boudreaux said.

“The very nature of Charlie Kirk coming in requires you take special attention to the nuances of what could possibly happen,” Boudreaux said. “He’s a high-profile name and personality. Not only do we have to provide for the safety of people attending, we have to provide for the safety of him.”

By contrast, Kirk’s outdoor event at Utah Valley University last week was held in an open space with far less security. Six campus police officers—about a quarter of the department—worked the event, which drew roughly 3,000 people, said Jeff Long, campus police chief. The department has not said whether it inspected nearby rooftops; the suspect shot and killed Kirk from atop a building hundreds of feet away.

As Kirk toured college campuses, he preferred to stay close to students, striking up conversations with passersby. His level of protection varied widely, with campus police often overseeing overall security, while Kirk’s private detail focused on close-up protection.

His assassination has prompted scrutiny of the role campus police play in protecting high-profile and divisive political figures. Security experts have questioned the number of officers deployed and the decision to hold the Utah event outdoors, placing Kirk in the direct line of sniper fire.

The Utah Department of Public Safety’s investigation into the shooting does not include the university’s security plan, Commissioner Beau Mason said. Utah House Speaker Mike Schultz, a Republican, indicated that lawmakers may review security protocols at Utah Valley in the wake of the attack.

At past events, security arrangements were stricter. In April, Illinois State University assigned more than a dozen campus police officers to a 700-person Kirk appearance, with additional officers monitoring cameras trained on nearby rooftops from an operations center. The University of Wyoming deployed about 15 officers for an indoor Kirk event the same month.

Outdoor events, experts say, are harder to secure. College campuses are generally open and accessible, making them vulnerable to shootings, said Don Aviv, CEO of Interfor International. “Without monitoring rooftop access and blocking shooter sightlines, it doesn’t matter how many armed personnel you have surrounding the speaker—you would not have been able to protect against a long gun,” Aviv said.

Kirk requested the Utah Valley event be outdoors to engage with students, spokeswoman Ellen Treanor told the Salt Lake Tribune. The up-close approach complicates security planning, said Aaron Woodruff, police chief at Illinois State University. “It makes it hard to protect somebody when you have people on all sides of him,” he said.

Security experts point to monitoring rooftops as critical. James Hamilton, founder of the FBI’s close protection school, cited last year’s attempted assassination of former President Donald Trump in Pennsylvania as a warning about sniper attacks. “Butler told people it’s not that hard to get a rifle, get up on a roof, and shoot,” Hamilton said.

Campus police at Utah Valley did not respond to requests for details on security planning or rooftop inspections. “This is a police chief’s nightmare,” Long said. “You try to get your bases covered, and unfortunately today we didn’t, and because of that we had this tragic incident.”

Turning Point USA, Kirk’s organization, said he had received “thousands” of threats but always prioritized connecting with young Americans over personal safety.