Homeland Security Investigations, ICE’s investigative arm, plays a front-line role in America’s counterterrorism response. It stands guard against terrorist threats and watches for new terrorist recruitment strategies.
As these dangerous criminals continue to change their tactics and strategies, ICE dismantles the threats terrorists pose to our homeland.
Lessons from 9/11: More coordination and collaboration
Before 9/11, inadequate coordination, communication, and exchange of national security information between law enforcement agencies were major obstacles in combating terrorism. However, after 9/11, the U.S. government created the Department of Homeland Security and ICE — and it significantly expanded the FBI’s Joint Terrorism Task Forces, which were first established in 1980 in New York City.
The JTTFs are FBI-led, multiagency teams that focus on preventing, investigating and responding to terror threats in the United States. Given ICE’s distinctive capabilities to counter terrorism efforts, ICE fills an extremely important position at the table. By being assigned to most of the 184 JTTFs nationwide, ICE is the largest investigative and longest-standing federal partner in this critical network. Through their presence on the JTTFs, ICE special agents and officers work collaboratively with the FBI.
ICE takes action against foreign terrorists moving money, weapons and people across international borders.
Evolving threats in the digital age
Since 9/11, the terror threat landscape has transformed dramatically.
A decade ago, international terrorist groups like al-Qaida published magazines and articles to drive their ideology. But today, groups like ISIS use social media in their recruitment efforts.
While lone-wolf style attacks like the Pulse nightclub shooting (2016), the New Orleans New Year’s attack (2025) and the Boulder attack (2025) have claimed several lives, no coordinated, large-scale terrorist attacks like 9/11 have taken place in the United States. That’s largely because of the U.S. government’s robust network of resources and tools that enable it to stay ahead of any major coordinated attack.
“We, as a U.S. government, have been doing a phenomenal job,” says HSI Counterterrorism Section Chief Diana Alvarez. “I’m privy to things I know could have happened that didn’t. We’ve learned to work better together. The task force model works because access that I don’t normally have becomes possible when we’re part of the same team.”
Red flags: Overstays and visa violations
When most people hear about terrorists, they normally think of guns and bombs exploding — but seldom notice the different disguises terrorists employ to reach their targets.
HSI’s Counter Threat Lead Development Unit focuses on a similar front: Identifying and investigating people who enter the United States legally on visas but then overstay or violate the conditions of their admission. This meticulous, data-driven work is indicative of a fundamental shift in how America protects itself in the post-9/11 era.
American embassies and consulates overseas work as the first line of defense, preventing known and suspected terrorists from ever coming to the United States.
Visa overstays
ICE takes visa overstays seriously — they can, and often do, lead to national security threats.
Someone who overstays a visa may end up working illegally, using a fraudulent Social Security number or engaging in other criminal activities. If they can’t get a job because they don’t have legal status, they might resort to theft.
When someone enters the United States, officials use government systems to indicate the purpose of their visit. When they don’t leave after their visa expires, the system triggers a notification to check their immigration status.
ICE’s Student and Exchange Visitor Program, managed by HSI, diligently oversees international students’ visa statuses. While most international students come here for education, fraud and criminal elements with ulterior motives constantly try to exploit our system — including those who work with “pay-to-stay” universities, which are fraudulent or illegitimate educational institutions primarily to help students maintain their visa statuses.
“It’s like drug trafficking organizations,” said one ICE official, referring to the fake schools that sponsor foreign students to come to the United States. “When you catch one, three more pop up. If someone finds a scam that works, it continues until we catch it, then they find a new method.”
Detecting and tracking people trying to circumvent our legal immigration system requires painstaking coordination and analysis.
At the time of the 9/11 attacks, the kinds of coordination and communication that exist today were not in place.
Today, ICE enjoys better resources, has access to consolidated databases, and engages in effective coordination with other government agencies to make sure people don’t slip through the cracks.
Bad actors evolve, so what works as a detection mechanism today may be obsolete tomorrow. This situation requires analysts to constantly look beyond current patterns to anticipate future threats.
ICE works closely with the U.S. Department of State to share fraud indicators and patterns to help the agency vet international visa applicants.
“Terrorism is basically about not letting you live your life comfortably,” said Counter Threat Lead Development Section Chief Richard “Rick” Phillips. “Anytime you’re thinking about or concerned about what you’re doing, terrorists have succeeded in getting you to live in a state of fear.”
Balancing security and opportunity
The United States constantly faces the challenge of balancing action against those who want to undermine national security and those who come here for legitimate reasons, like higher education and tourism.
ICE’s constant vigilance — a hard-earned lesson from the 9/11 attacks — may be invisible to the public, but it is crucial in protecting American communities. The agency’s proactive stance allows it to respond to threats quickly, before apparently minor issues like visa violations turn into more serious issues.
Twenty-four years after 9/11, the threat landscape has evolved dramatically — but so has ICE’s ability to detect and respond to potential dangers. Through meticulous investigative work, international cooperation and adaptation to new challenges, ICE plays a tremendous role in preventing another terrorist attack like Sept. 11.
“We don’t know what the next method is going to be,” said Phillips. “But our eyes are open. We want to see the big picture and look for things that are intentionally being hidden from us.”