Scrutiny intensifies over security lapses surrounding the Charlie Kirk shooting

"Universities have so many speakers that come on campus all the time. Rarely do they plan for somebody taking a longer-range shot with a rifle," explained retired Marine Lt. Col. Hal Kempfer in an interview with Fox News Digital.

"Sniper assassinations are far less common and even in active shooter scenarios, usually the active shooter gets into a closed space where the person is very close to where the victims are," he said, noting the immense difficulty of defending against an assailant who can strike from a concealed, elevated, or distant position.

"It's a lot more involved to carry out and plan for counter-sniper missions," Kempfer said, emphasizing that this level of violence was never anticipated at what was meant to be a debate-style discussion.

The revelation underscores an unprecedented challenge confronting law enforcement as they work to protect political rallies on college campuses and in communities nationwide. 

"The campus has limited security. They don't have an unlimited budget for this. They had six officers out there, which for any college campus security force, that's not an insubstantial number of officers. But they also had 3,000 people at this event," Kempfer said.

In addition to local security, Kirk, who spoke outdoors, was flanked by his personal security detail. 

Despite those measures, former FBI special agent Stuart Kaplan said the gunman may have established his position on the rooftop ahead of time, which made it difficult for security to spot him.

"He was clearly undetected, there was no indication that anybody saw him on this rooftop," Kaplan told Fox News host Jesse Watters in an interview on Wednesday. "This was a very well-planned, very well-orchestrated plot that was put in motion days before," he said, adding that the suspect "had some level of sophistication to have mapped out exactly how this was going to go down."

That assessment was echoed by former New York State Senator and Homeland Security advisor Michael Balboni, who said, "One shot hitting the target from 200 meters away and then escaping without anybody seeing them-those are the hallmarks of a professional."

"The hardest thing to do is anticipate where the threat comes from and what threats there are. I would argue that in an open air setting like this, a rifle attack is probably the most difficult thing to stop," Balboni added in an interview on Fox News 5. 

Kaplan said that the gunmen also thought through how to evade law enforcement after taking the fatal shot. 

Kempfer noted that the gun recovered by authorities on Thursday was a bolt-action rifle, a common hunting weapon valued for its durability and reliability. Unlike semi-automatic weapons, he explained, a bolt-action rifle often retains the spent cartridge in the chamber rather than ejecting it, leaving no shell casings-or "brass"-for investigators to collect.

"That's just one of those things where you, if you've thought it through, you know that you can't leave any forensic evidence for investigators to work with," he said.

In a photo released on Thursday, the individual authorities were looking for was wearing a hat, sunglasses, and an American flag T-shirt with an eagle on it.