A former FBI agent says the number of people who overstay their visa in the U.S. is a “national security issue” following the terror attack in Boulder, Colorado that left 15 people injured.

Mohamed Sabry Soliman, who’s suspected of firebombing a group of peaceful pro-Israel protesters on June 1 leaving 15 people injured, arrived in the United States on Aug. 27, 2022 on a B1/B2 non-immigrant visa, sources told Fox News. His visa was set to end on Feb. 26, 2023, but he received work authorization. Soliman is an Egyptian national.

Soliman’s work authorization ended in March 2025, around three months before he allegedly attacked the group of pro-Israel protesters. 

A report from the Department of Homeland Security shows around 400,000 individuals were suspected to have overstayed their visas in fiscal year 2023, the most recent year there’s government data on the issue. These are individuals who lawfully obtained a visa to enter the United States, but didn’t leave when they were supposed to.

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Former FBI special agent Jonathan Gilliam told Fox News Digital visa overstays are a national security issue.

“I think we’ve shown that it’s a national security threat. We’ve shown just by what we’ve seen in Boulder, Colorado, but… there’s numerous other issues that have occurred in this country by people who have overstayed their visas, and I don’t believe that people understand the numbers of these individuals,” Gilliam said.

Between fiscal years 2020 and 2023, Department of Homeland Security data shows that over 1.5 million people have overstayed their visas.

Gilliam said the longer it takes for reforms to be implemented to the visa system, the likelihood of another attack only increases.

“All of this has to be looked at, but just looking at what happened in Boulder, that could happen over and over again because the system of monitoring people who are here on a visa is almost nonexistent once they get in here,” Gilliam said. “And if they’re idealistic or if they get cultivated to believe in a radical way, there’s nothing stopping them.”

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One thing Gilliam said should be looked at is monitoring people who are in the U.S. on visas, as he says there are enough systems in place to track those individuals in real time.

“We have to come up with better ways to track them, people who will vouch for them. And if we have that in place, along with policies that back the laws, it’ll be much easier to determine who is here, where they are, and if they’ve overstayed,” he said.

While Soliman was in the United States on a B1/B2 visa, he obtained work authorization that allowed him to have jobs at Vero Health and Uber.

A spokesperson for Vero Health told Fox News Digital that Soliman worked at the company for around three months, but didn’t explain why he left.

“He was hired in our accounting department. He went through a hiring process with ADP, our employer [Professional Employer Organization]. At the time of hire, he was confirmed to have a valid work visa, which was noted to expire in March 2025,” the spokesperson said.

Uber also confirmed to Fox News Digital that Soliman began driving for the company in the spring of 2023, and passed a criminal and driving history background check.

Soliman was charged with first-degree murder, crimes against at-risk adults/elderly, first-degree assault, criminal attempt to commit class one and class two felonies, and use of explosives or incendiary devices during a felony.