Like other community activists, protesters and passersby around the U.S., McLellan took photos, including of an arrest. Then she followed a federal officer driving an unmarked vehicle to see where the agent was headed next.
McLellan was surprised when the agent led her to her own house and blocked her driveway. Other federal officers quickly arrived, boxing in her car with their own vehicles.
“This is a warning,” an agent told her, according to court records and a video recording. “We know you live right here.”
Liz McLellan took this photo of federal immigration agents making an arrest on Jan. 21 in Westbrook, Maine. Then an agent held up his phone to McLellan’s face. Agents went to McLellan’s house not long after. Liz McLellanIn the battle against illegal immigration, the U.S. is spending hundreds of millions of dollars on tools that give federal agents easy access to the home and workplace addresses of American citizens, their social-media accounts, vehicle information, flight history, law-enforcement records and other personal information, as well as data to track their daily comings and goings, The Wall Street Journal found.
This newly expanded domestic surveillance system, a high-tech dragnet built to locate, track and deport people residing illegally in the U.S., allows thousands of federal agents nationwide to peruse a trove of data belonging to more than 300 million people, including citizens.
The government's tracking system relies on an amalgam of public and private information sifted, sorted and packaged by contractors that include Palantir Technologies, Deloitte, Japanese conglomerate NEC and smaller spyware specialists.
The Department of Homeland Security has put these surveillance tools—facial-recognition software, location tracking and social-media scrapers once aimed largely at suspected terrorists and drug-traffickers—in the hands of federal immigration agents, who can identify, research and track virtually anyone by entering a name, license plate or by simply taking a person's photo.
The government surveillance system has advanced since the 9/11 terrorist attacks with the aid of artificial intelligence and the linking of government records with far-reaching commercial databases. It has been used against people whom the government alleged opposed or obstructed the immigration crackdown.
As agents gain more powerful tools—including the ability to crack encrypted messaging apps and scan a person’s WhatsApp and Reddit—department limits on their use are shrinking, according to interviews and a Journal review of DHS policy documents.
Privacy experts and former department employees say the administration is aggressively interpreting existing rules and ignoring limits set by prior administrations. The immigration crackdown is testing the legal and ethical boundaries of citizen surveillance and privacy rights, according to former department officials.
In addition to McLellan, 48 years old, at least four other Maine residents say they were singled out and threatened after observing the work of federal agents, according to court records. Two of the people in a continuing civil rights lawsuit accuse DHS of unlawfully using their license plates and biometric data to track and intimidate them for exercising their First Amendment rights. DHS said it operates in full accordance with the law.
“The retaliation we’ve seen against Americans who chose to lawfully record DHS activities should alarm everyone,” said Rush Atkinson, a former Justice Department attorney who is representing the two people in the case. “This is a fundamental First Amendment right, and the public has the right to know why the government is collecting data on those who peacefully protest.”
Observers recording ICE agents on Feb. 5 in Minneapolis. Stephen Maturen/Getty Images
Federal immigration agents knocking at a residence in Minneapolis on Jan. 9. Bridget Bennett for WSJWith the backing of Congress and President Trump, DHS spent a record $425 million on surveillance tech in the past year, a 17% increase from the prior year. Federal spending is on pace to set another record in 2026, according to an analysis of federal contract data by the Journal. DHS received $191 billion for immigration enforcement in last year’s One Big Beautiful Bill Act.
Some Democratic lawmakers have questioned the department’s use of surveillance technology, including cellphone hacking tools. In response to those concerns, the DHS inspector general announced in February an investigation into the department’s collection of biometric data.
Civil rights groups and others have filed four federal lawsuits alleging the department’s use of surveillance tools to revoke visas and arrest immigrants without warrants, or to threaten bystanders observing federal agents, were all violations of the Constitution. DHS denied wrongdoing in those cases.
Enforcing immigration law “is essential to protecting America’s national security, public safety and economic strength,” DHS said in response to questions.
Immigration and Customs Enforcement is responsible for tracking more than 7 million immigrants, including those ordered out of the U.S., released from detention or who await an immigration court hearing, DHS said.
“We are not going to divulge law enforcement-sensitive methods,” DHS said, but the department employs various forms of technology, while “respecting civil liberties and privacy interests.”
“We do of course monitor and investigate and refer all threats, assaults and obstruction of our officers to the appropriate law enforcement,” DHS said. “Our law enforcement methods follow the U.S. Constitution.”
Who’s who
Palantir is the top beneficiary of DHS’s stepped-up spending on deportation and surveillance work, according to a Journal review of government records, contracts, documents describing privacy concerns and people familiar with the matter.
Palantir quadrupled its DHS contracts to $81.3 million after Trump’s return to the Oval Office last year, largely for work linking data streams for use in immigration enforcement. The department in February signed a four-year, $1 billion blanket agreement that allows for continuing work from the Miami-based data analysis company.
Last year, DHS paid Palantir $30 million to put a broad span of information about individuals into an app on agents’ smartphones, allowing them to plot the location of people in the U.S. The app, known as Enhanced Leads Identification and Targeting for Enforcement, or ELITE, lets officers research and track individuals based on criminal history, license plate searches, name, date of birth or locations.
The results display on a map or as a list, according to ICE agents. The app pulls from a variety of government databases, including information compiled by private investigators known as “skip tracers” who track the current addresses of individuals. “Our work is focused on the address fidelity of noncitizens,” a Palantir spokeswoman said.
An ICE agent during court testimony last year compared ELITE to Google Maps: Targets appear as pins on a map, clustered around addresses where immigrants, including “lawful permanent residents,” are likely to live, court records show.
Federal immigration agents chatting in April at the Border Security Expo in Phoenix. Rebecca Noble/Reuters
Palantir CEO Alex Karp speaking with employees at a company office in Washington last year. Stephen Voss for WSJImmigration agents used ELITE to identify an apartment complex outside Portland, Ore., in a town populated by agricultural workers, according to court records. On an early October morning, federal officers watched a white van leave the parking lot.
They radioed the van’s license plate number to a field team, and the query returned the name of an immigrant on their target list. Agents pulled the van over and, without a search or an arrest warrant, handcuffed the driver and passengers, according to court records from a continuing federal lawsuit.
One ICE agent testified in court that the arrests were justified because at least one individual refused to share their name. That made the individual a flight risk with “no way to go locate this person again,” the agent said. Immigration law allows officers to make warrantless arrests if someone is both in the U.S. illegally and likely to escape before a warrant can be obtained.
In February, the federal judge in the case found that ICE was “casting dragnets over Oregon towns” and held that warrantless arrests made, in part, from use of ELITE violated the Constitution because federal agents determined several people were flight risks only after they were in custody—rather than because agents had probable cause before making an arrest.
A federal immigration agent using a facial recognition tool on a person at a hearing with his family last year at an immigration court in New York. The man was detained briefly and released. David Dee Delgado/Reuters
Visitors leaving a detention facility used by ICE last year in Adelanto, Calif. Patrick T. Fallon/AFP/Getty Images
Through the year beginning in January 2025, the U.S. paid consulting firms, including Deloitte, $130 million, to aid ICE’s deportation efforts and law enforcement support work. New consultant contracts call for analysts to monitor people on social media, identify threats and create dossiers about people who make them.
DHS awarded $15 million to tech company Cellebrite for forensic tools to unlock phones and extract call logs, GPS location data, text messages, deleted photos, contacts and email addresses, DHS documents show. CBP renewed agreements with vehicle-forensics firm Berla to retrieve data, including travel history, from the vehicles of suspects.
Last year, DHS reactivated a $2 million contract with the U.S. subsidiary of Israeli spyware company Paragon Solutions, which makes Graphite, a hacking tool that can infiltrate encrypted messaging apps such as Signal and WhatsApp.
ICE agents can access vehicle information and travel history from databases that collect information from electronic license-plate readers installed on highways and at the U.S. border. DHS paid $20 million last year to data brokers, including Thomson Reuters and LexisNexis, which said its tools aren’t used for “monitoring.”
Nearly $21 million went to companies that track and identify targets with biometric technology. That included $8 million to NEC for a facial-recognition algorithm that identifies passengers boarding planes. DHS rolled out an app last year that allows agents to identify people from images, using NEC technology. DHS also expanded its use of Clearview AI, another facial-recognition database, which contains more than 70 billion photos.
NEC, which for years has aided airport screening for CBP, processed photo images of roughly 200 million travelers, according to congressional testimony. “We provide technology in accordance with U.S. law and contractual agreements,” an NEC spokesperson told the Journal.
In March last year, DHS deployed Mobile Fortify, an app that allows agents to point their phone camera at a person’s face and retrieve names, birth dates, citizenship or immigration status and information about family members, government documents show.
Around the same time, DHS officials deleted policy memos that set limits on the use of facial recognition in investigations, according to former department officials. The department archived and later restored mention of a policy that said the government can’t investigate individuals lawfully protesting government activities.
One DHS staffer who worked last year in the office that developed policies on border and immigration practices said even his team wasn’t sure what the agency’s rules were.
DHS policies governing facial-recognition and face-capture technologies remain unchanged, the department spokeswoman said.
In the Oregon case, agents took a photo of one individual and Mobile Fortify gave two possible identities, both of them wrong, according to court records.
‘Domestic terrorist’
In October, Marimar Martinez, en route to a Chicago church to donate clothes, saw an unmarked vehicle she suspected was carrying federal agents. She called out a warning to residents in Spanish, La migra! La migra!
Martinez, a 31-year-old teaching assistant, had no clue she was under government watch.
Marimar Martinez, a U.S. citizen who was shot by a Border Patrol agent in 2025, at a relative’s home on April 11 in Chicago. Jamie Kelter Davis for WSJFederal agents knew Martinez had reshared a Facebook post ostensibly identifying an immigration officer’s personal YouTube account. Within a day of her sharing the post, CBP circulated her name and photo with a warning to agents in the field: Martinez, a U.S. citizen, was a potential threat.
She was following the unmarked vehicle and shouting her warning less than a week after she drew the government’s scrutiny. The two vehicles collided, officers got out and the driver, a Border Patrol agent, shot her five times.
Martinez, who survived her injuries, was called a “domestic terrorist” by DHS officials. She was charged with assaulting an officer by using her car as a weapon, a felony crime that carried a maximum prison sentence of 20 years.
Martinez said the vehicle carrying federal agents sideswiped her. “They said I, quote unquote, rammed federal agents,” she said at a congressional hearing in February. “If they only knew I was a month away from paying off my truck, and I would never intentionally damage my vehicle, much less be crazy enough to hit” law-enforcement officers.
Body camera video from a responding officer shows Border Patrol Agent Charles Exum exiting the vehicle with his gun drawn. The shots he fired at Martinez can be heard seconds later. Cheronis & Parente LLC
A photo of Marimar Martinez’s injuries after her shooting by a federal agent in October 2025. Jamie Kelter Davis for WSJFederal investigators used data from a network of license-plate readers and traffic-surveillance cameras collected by local police to retrace her movements in the days before the shooting, court documents show. They showed her running errands and commuting to work, according to Martinez’s lawyer.
The tracking information originated from Flock Safety, which contracts its services to about 100 police departments in the Chicago metropolitan area. “It is not Flock’s job to determine who should share or collaborate with the federal government,” said Joshua Thomas, a spokesman for the company, which operates in 49 states.
The government moved to drop its case against Martinez a month after the shooting, and the judge dismissed the charges.
Martinez would see her bullet scars for life, she said at the congressional hearing, but “perhaps even worse, the mental scars will always be there as a reminder of the time my own government attempted to execute me.”
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Appeared in the May 2, 2026, print edition as '‘We Know You Live Right Here’: No Secrets in America’s New Surveillance Dragnet'.