FBI, lawmakers raised border security concerns prior to Boulder terrorist attack

Lawmakers and intelligence experts have been sounding the alarm about potential terrorism threats stemming from those in the U.S. illegally long before Sunday’s terrorist attack injured eight people in Boulder, Colorado. 

first reported that the suspect involved in the attack originally entered the U.S. under the Biden administration and had overstayed his visa.

But various officials have long cautioned about the risk of terrorism due to lax border security. 

For example, then-chair of the House Permanent Select Committee on Intelligence Chair Mike Turner, R-Ohio, and House Homeland Security Committee Chair Mark Green, R-Tenn., raised concerns in August 2024 after a report from House Judiciary Committee Republicans found that the Biden administration released nearly 100 illegal immigrants into the U.S. 

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“Since the Biden-Harris Administration’s failed open border policies have welcomed potential terrorists into our nation, we’re working to combat these threats and safeguard Americans in their own backyards,” Turner and Green said in a joint statement in August 2024 in response to the report. 

Meanwhile, the FBI has previously issued similar concerns about foreign terrorists entering the U.S. and conducting attacks against American citizens. 

“I have warned for some time now about the threat that foreign terrorists may seek to exploit our southwest border or some other port of entry to advance a plot against Americans,” former FBI Director Christopher Wray told the House Judiciary Committee in April 2024. “Just last month, for instance, the Bureau and our joint terrorism task forces worked with ICE in multiple cities across the country as several individuals with suspected international terrorist ties were arrested using ICE’s immigration authorities.”

Wray said in 2024 that those arrests involved hundreds of FBI employees to properly identify dangerous individuals. But the use of false documents from those crossing the border amplifies concerns related terrorism threats, and makes it even more challenging for FBI employees to track down, Wray said. 

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FBI Director Christopher Wray resigned from his post leading the FBI in December.  (Julia Nikhinson/Getty Images)

“As concerning as the known or suspected terrorists encountered at the border are, perhaps even more concerning are those we do not yet know about because they provided fake documents or because we didn’t have information connecting them to terrorism at the time they arrived in the United States,” Wray said. 

Meanwhile, Democrats have claimed that U.S. citizens are primarily responsible for conducting terrorist activity in the U.S. For example, House Border Security and Enforcement Subcommittee ranking member Rep. Lou Correa, D-Calif., pointed to a study from the Cato Institute that found that no people were murdered by a foreign-born terrorist who entered the U.S. illegally between 1975 and 2022. 

“Most terrorist activity is conducted by U.S. citizens,” Correa said in September 2024. “Again, zero Americans have been injured or killed by terrorist attacks perpetrated by undocumented immigrants who entered through the southwest border. However, DHS and the FBI regularly tell us that one of the greatest terrorist threats to our homeland is domestic terrorism.”

Law enforcement officials said that Mohamed Sabry Soliman, 45, yelled “Free Palestine” and used a makeshift flamethrower to attack those attending an event in Boulder, Colorado, organized by “Run for Their Lives,” a grassroots group that holds events urging the release of Israeli hostages. 

Soliman was in the U.S. illegally after his visa expired, three Homeland Security and U.S. Immigration and Customs Enforcement sources told . Soliman entered the U.S. in 2022 on a nonimmigrant visa, and eventually obtained work authorization — but that expired in March. 

FBI Deputy Director Dan Bongino said FBI officials are coordinating with local law enforcement to investigate the attack. 

“We are investigating this incident as an act of terror, and targeted violence,” Bongino said in a post on X on Sunday. 

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An Israeli flag is fixed to a street sign as police stand by off Pearl Street on the scene of an attack on demonstrators calling for the release of Israeli hostages held in Gaza, in Boulder, Colorado, on June 1, 2025.  (ELI IMADALI/AFP via Getty Images)

Meanwhile, the Trump administration has chastised the Biden administration for its immigration policies that facilitated Soliman’s entry to the U.S.  

“A terror attack was committed in Boulder, Colorado by an illegal alien,” White House Deputy Chief of Staff Stephen Miller wrote on X. “He was granted a tourist visa by the Biden Administration and then he illegally overstayed that visa. In response, the Biden Administration gave him a work permit. Suicidal migration must be fully reversed.”

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Meanwhile, Green described the attack as a “wake-up call” regarding growing terror threats jeopardizing safety in the U.S. 

“This is another wake-up call to the heightened terror threat facing the United States — and to the fact that the enemies of freedom are persistent,” Green said in a statement Sunday. “I am requesting a briefing from DHS for House Homeland Security Committee members as soon as department officials are available to provide one.”

The Associated Press contributed to this report.