New York City dodged a bullet in April when a federal judge allowed the destruction of more than 900,000 records of applicants for IDNYC, a citywide identification card program that was heavily marketed towards the vast local population of undocumented immigrants. Late last year, two state lawmakers from Staten Island filed suit under New York State’s Freedom of Information Law seeking to prevent the city from destroying the application documents for more than 900,000 city residents who had received cards through the program, IDNYC. While Assembly members Ron Castorino and Nicole Malliotakis claimed their suit had nothing to do with immigration policy, advocates and city officials saw the lawsuit as a thinly veiled attempt to preserve records that could assist Immigration & Customs Enforcement in deportations. Malliotakis has since vowed to appeal the judge’s ruling.

After Trump’s election, New York City joined municipalities around the country in announcing itself as a “sanctuary city,” a place where law enforcement would refuse to help in the deportation of as many as 11 million undocumented residents Trump threatened he’d target while on the campaign trail, and appears to be making good on his promise with a 40 percent increase in immigration-related arrests by ICE through the beginning of May. After more than 160 people were detained by ICE in the Los Angeles region in February during nationwide immigration enforcement actions, Mayor Eric Garcetti vowed to do “everything in my power … to make sure that the legal rights of all Angelenos are respected and upheld at every stage of the enforcement process.” In Santa Cruz, where a number of undocumented people with no criminal history were detained and placed in removal proceedings during a federal gang sweep, the local police chief denounced ICE for not notifying his agency. And in California, a bill that would restrict state agencies and law enforcement from cooperating with ICE for immigration enforcement in all but a few circumstances has already passed the state Senate and has the support of the Assembly majority and Gov. Jerry Brown.

However, the ever-expanding amount of information collected about individuals by government and private entities means that despite their good intentions, cities with sanctuary policies may be inadvertently assisting ICE through personnel and information-sharing agreements with the federal government. And the law may not be on their side.

  • At the heart of ICE's cooperation with local law enforcement is communication and information sharing.

Advocates have long warned that even ID programs like New York’s — which aimed to bring undocumented residents out of the shadows — could put those same residents at risk if ICE got its hands on any revealing paperwork. And some cities took heed: San Francisco’s municipal identification program, created in 2009, immediately destroys all materials provided by applicants. But for the many others that haven’t taken such steps, data like the application materials for New York City’s municipal identification cards has moved to the center of the battle between Washington, D.C., and local governments over immigration policies.

For all the tough talk by cities that have announced their intention to stand up to the president’s deportation plans, once such data is collected and saved there is little they can do to monkey-wrench ICE’s enforcement operations.

Shifting Strategies

In the days of George W. Bush’s presidency, the hallmark of ICE’s work was large-scale workplace raids, intended to target industries with high numbers of undocumented workers. Those days are over: today, information is the lifeblood of Immigrations and Customs Enforcement. According to the Immigration Law Resource Center, ICE’s main enforcement programs revolve around data mining information provided by local jails or criminal intelligence. “At the heart of ICE’s cooperation with local law enforcement is communication and information sharing,” says the Immigration Legal Resource Center in a primer on ICE’s enforcement methods.

The problem for sanctuary cities, however, is that their right to withhold such data from federal immigration authorities is far from established. A series of laws passed in 1996 during the Clinton administration’s crackdown on illegal immigration — most notably the Illegal Immigration Reform and Immigrant Responsibility Act — established that local governments are not mandated to provide information to the federal government, but also that they cannot block ICE’s access to records they maintain, or from preventing individual employees from cooperating with federal immigration authorities.

  • “Once you've given people access to databases, how do you pull back? I don't think you can.”

Two subsequent court decisions have backstopped this position, and have provided the Trump administration with some tenuous legal groundwork to support Attorney General Jeff Sessions’s threat to withhold federal money from recalcitrant sanctuary cities. However, the scope of the federal government’s ability to mandate cooperation from municipalities for immigration enforcement is far from settled, as demonstrated by U.S. District Court Judge William Orrick III’s April 25 decision blocking President Trump’s executive order threatening to withhold funding from sanctuary cities. Despite Judge Orrick’s ruling, the Trump administration’s recent budget proposal includes language that would allow the Justice Department and Homeland Security to deny funding for municipalities that attempt to deny records to ICE.

The explosion of data that has taken place since the turn of the millennium has revolutionized law enforcement, giving police departments and federal agencies alike access to tools that provide quick access to financial records, drivers licenses, vehicle records, telephone calls, and criminal justice records. These tools didn’t exist when the 1996 law was passed, but as a consequence of its passage, immigration authorities now have access to vast repositories of information on people that simply did not exist two decades ago.

“Once you’ve given people access to databases, how do you pull back? I don’t think you can, said Maria Blanco, a professor of law at the UC Davis School of Law and the executive director of the Undocumented Student Legal Services Center, which represents young people who received legal status through the Obama-era Dream Act program.

ICE’s increased use of data mining to identify and locate undocumented people is reflected in the nature of recent enforcement operations since Donald Trump’s January inauguration. Immigration attorneys and advocates interviewed for this story indicated that many of the people picked up by ICE during enforcement operations this winter were identified as having outstanding removal orders. Others, like Washington State Dream Act recipient Daniel Ramirez Medina, detained by ICE while the feds were looking for his father, were caught up during a search for another individual. “The raids are different than before, they’re very targeted,” said Ana Muniz, an assistant professor of Criminology, Law & Society at the University of California, Irvine. “Any sort of motivated agent has a way to access information from one system to another. The arrests we’re seeing in Los Angeles are of ICE agents sent out to detain or one two people with specific standing removal orders, that requires a detailed level of intelligence, whereas during the 1990s and 2000s, the raids were more location-based,” Muniz said.

The removal proceedings of a young Central American man for alleged gang ties in Boston, a key sanctuary city, elucidates ICE’s reliance on information gathered by local police.

In 2015, while in high school in a heavily Latino area of Boston, the young man was in the cafeteria when an argument broke out among several other students. Although no fight ensued, Boston School Police reviewed video footage of the incident and documented him as an “MS-13 Associate” — referring to Mara Salvatrucha, a well-known transnational gang. No suspensions or disciplinary actions were meted out as a result of this incident, according to Sarah Sherman-Stokes, an attorney at Boston University’s Immigrant’s Rights Clinic who represented the young man. However, the police report was forwarded to the Boston Regional Intelligence Center (BRIC), the local fusion center where Boston cops work side by side with personnel from the FBI and ICE. That fusion center’s privacy policy allows for the sharing of information even without any suspicion of criminal wrongdoing.

Sherman-Stokes says documents and court testimony she obtained reveal the information in the school police report prompted agents from ICE’s Homeland Security Investigations arm to scour her client’s Facebook account, which yielded photographs of him wearing blue, white, and red clothing that the feds claimed constituted gang membership. Sherman-Stokes said one of those photographs was taken on the day of a Salvadoran parade in Boston when her client was wearing blue and white, the colors of El Salvador’s flag. Despite her challenges, an immigration judge ruled the young man was a gang associate, and he was ordered removed. The case is currently on appeal, and the man, now 20, has been in immigration detention for more than six months. (The Intercept is withholding his name because some of his relatives are also undocumented.)

“My client was going to school full-time and working at a restaurant from 5 p.m. to midnight — he didn’t have time to be a gang member,” Sherman-Stokes said, noting that the young man has no arrests, or any other indication of gang affiliation other than the lunchroom incident. “What has happened is that every behavior problem of a young brown person has become a gang problem,” said Sherman-Stokes. “I sincerely doubt that a lunchroom dispute would result in this information being sent to BRIC were they not poor kids of color.”

Pathways to Immigrant Data

In 2014, after President Obama announced his “felons not families” policy, ICE shifted its focus away from all immigrants without documentation and toward violent criminals and alleged gang members. That narrowed mandate coincided with attempts in cities like New York and San Francisco to give undocumented immigrants municipal identification cards, driver’s licenses, and financial aid for higher education.

“For the last eight years, we’ve lived in an environment where the basic assumption has been we can give undocumented people benefits for coming out of the shadows, with few or any risks,” said Alvaro Bedoya, the director of the Center for Technology and Privacy at Georgetown Law, which is currently researching the impact of government surveillance on communities of color.

“That time,” Bedoya adds, “is over,” and is marked most dramatically by two memos issued in February by Homeland Security Secretary John Kelly that essentially re-prioritized all the estimated 11 million undocumented immigrants in the United States for deportation, regardless of their criminal history, family ties, or asylum claim.

Consequently, Beyoda said, cities that have adopted data collection and dissemination as a model of public service over the past decade need to comprehensively review what information they collect, what impact it could have on residents’ lives, and whether it needs to be gathered at all.

“A foundational principle of privacy by design is data minimization at the outset, and jurisdictions need to think about whether they need to collect all the data they do collect,” he said.

In New York, Los Angeles, Chicago, Boston, Washington, D.C., Oakland, and Seattle — some of the nation’s largest and most outspoken sanctuary cities — local police departments have officers working side-by-side with ICE agents in joint task forces. These cities also maintain databases of criminal and non-criminal information that immigration authorities can request to identify and locate undocumented residents. This non-criminal background includes information such as parking violations, business records, and employment information. ICE also relies on biographical and biometric information from jailhouse bookings and field contacts, which are fed into the FBI’s National Crime Information Center and Next Generation Identification System databases.

One key conduit of information from local police to ICE is through joint federal-local task forces intended to combat crime or terrorism. Police officers in each of the listed “sanctuary cities” that choose to participate are assigned to the local Joint Terrorism Task Force. Though the JTTFs are run by regional offices of the FBI, agents from ICE’s Homeland Security Investigations are assigned to all 104 such task forces across the country, and ICE’s own website boasts that the agency “is the largest federal contributor to the JTTF.”

Furthermore, police in several cities (Los Angeles, Oakland, Santa Cruz, and San Francisco) have assigned other officers to participate as deputized federal agents in task forces run by ICE’s Homeland Security Investigations unit. The task forces are intended to focus on gun violence, gang crimes, and organized crime. According to ICE’s own documentation, local police officers who are deputized as federal agents cannot enforce immigration law. However, HSI receives access to local case files through these task forces, and the task force agreements do not bar HSI agents from detaining people for immigration violations during their joint operations with local police. Nor do the agreements place restrictions on ICE’s access to data maintained by local police or other municipal agencies.

Since at least 2010, LAPD has cross-designated officers as ICE agents for the Los Angeles Border Enforcement Security Task Force, one of ICE’s regional human- and drug-trafficking units. In a telephone interview, Mike Downing, the deputy chief for LAPD’s Counter-Terrorism & Special Operations Bureau, said the deputized police officers are not permitted to enforce immigration law. “All investigations involving LAPD officers have to have a criminal predicate, either reasonable suspicion or probable cause,” Downing said. The LAPD’s agreement was crafted to comply with Special Order 40, a 1979 policy directive that bars officers from arresting people for their immigration status alone. However, LAPD has no control over what ICE agents do while working alongside their officers, as evidenced by joint gang operations that have been criticized as end runs around Special Order 40. As a result, LAPD’s participation in task forces with ICE facilitates the agency’s enforcement of immigration law, even for undocumented people caught up during searches who may have committed no crime.

ICE has another pathway to local law enforcement data: through the dozens of intelligence fusion centers set up by the Department of Homeland Security across the United States after 9/11. There are 72 such entities around the country, which facilitate the sharing of information between local police, federal law enforcement, and the private sector.

These entities, such as the Joint Regional Intelligence Center in Los Angeles County, also store and disseminate license plate reader information to various law enforcement agencies, including ICE. License plate readers record every car that passes and mark the location and time of the photograph. Over time, license plate reader data can create a detailed and revealing portrait of someone’s private life and movements.

In Northern California, ICE agents have queried a vast repository of license plate reader data warehoused at the regional fusion center, according to statistical records obtained from the Northern California Regional Intelligence Center by privacy activist Mike Katz-Lacabe. And once localities like San Francisco or Houston allow a fusion center to access and store their license plate reader data, they cannot control who uses it.

In 2014, public outcry forced ICE to back down from a plan to purchase a subscription to the billion-record repository of license plate reader data from across the United States maintained by the private company Vigilant Solutions. Activists feared that ICE’s access to Vigilant’s enormous repository of vehicle data could allow federal agents to track an untold number of people without warrants. “If this goes forward, DHS will have warrantless access to location information going back at least five years about virtually every adult driver in the U.S., and sometimes to their image as well,” Gregory T. Nojeim, senior counsel for the Center for Democracy & Technology, told the Washington Post. However, ICE field offices in Newark, Houston, and Dallas used their own funds to purchase subscriptions to Vigilant’s database, providing the agency with access to more than 6 billion pieces of location data around the country. The Dallas office is home to ICE’s National Gang Unit, which tracks individuals across the country. Other ICE offices that have used Vigilant’s data are in Seattle, Los Angeles, Vermont, San Antonio, New Orleans, and Washington, D.C.

Records obtained by the Electronic Privacy Information Center indicate there was internal disagreement about how ICE should use license plate reader data. “There is no accountability to the public as to how the data is collected, how much is collected, how long it is retained, how it is used or what rights affected users might have,” ICE privacy officer Lyn Rahilly wrote in January 2011 to HSI officials regarding the use of Vigilant’s license plate reader data by the Houston and Newark offices. “I certainly understand why law enforcement would want to use this dataset,” Rahilly wrote. “But the public policy, privacy and civil liberties issues associated with its use are not insignificant.”

ICE is also using powerful cellphone tracking devices known as cell site simulators to locate undocumented people. In May, the Detroit News published a judicial warrant permitting ICE to use the cellphone tracking to hunt down a restaurant worker who had been deported twice before. ICE also recently beefed up its ability to extract and analyze cellphone data. In March, ICE’s National Mission Support office in Dallas purchased $2.2 million worth of cellphone and computer-cracking technology from the Israeli firm Cellebrite, significantly expanding the agency’s ability to extract data from seized electronic devices.

ICE also routinely mines information from state gang databases to identify undocumented people accused of affiliation or membership. Until ICE pulled the plug on its ICEGang database in October 2016, immigration authorities could access electronic gang files in 14 states that used the same software platform sold by CSRA International, a major defense contractor. The state gang databases are still in operation, and CSRA retains its own copies of the data collected and shared by local law enforcement. In the past, CSRA has turned over data to other government entities, such as the California State Auditor, and it is highly likely that CSRA will comply with similar requests from ICE for state gang data.

Immigration and Customs Enforcement — Primary Data Mining Tools

The centerpiece of ICE’s ability to identify and locate people under investigation for criminal or immigration offenses is the agency’s robust data mining capability.


A customized version of Palantir’s Gotham software, Integrated Case Management will soon replace the aging TECS (Treasury Enforcement Communications System) mainframe database and will then serve as the central repository of information for ICE’s criminal and immigration investigations. ICM reportedly will contain telecommunications data intercepted by ICE, location data from GPS trackers and license plate readers, financial transactions, and will access the FBI’s National Crime Information Center (NCIC) system which provides information on people arrested by local police across the United States.


Shared with Customs and Border Protection as well as United States Citizenship and Immigration Services, the Enforcement Integrated Database consolidates biometric and biographic information on people arrested by ICE and serves as the central repository for information on people contacted by ICE or other DHS agencies during immigration and criminal operations. EID also sends notifications to local and state law enforcement when people convicted of violent or serious crimes such as murder or rape are released from ICE custody in their jurisdiction.


Customized Palantir Gotham link-analysis software, operational since 2011, that establishes a portrait of a person’s movements, relationships, whereabouts, and financial background. Unlike ICM, which will be a digital workspace that provides access to criminal and immigration investigative files, FALCON-SA is an analytical tool that is programmed by ICE analysts to collate disparate information about investigative targets. FALCON-SA routinely receives data dumps from federal and local law enforcement criminal databases, telecommunications information from HSI investigations, suspicious activity reports, U.S. and foreign financial data, and tax information on watchlisted individuals. FALCON-SA users can also incorporate biographical information from private third-party databases such as Thomson Reuters’ CLEAR and Dun & Bradstreet and can access the FBI’s National Crime Information Center, and INTERPOL red notices.


A database and information analysis tool used by agents from HSI and ICE’s Counterterrorism and Criminal Exploitation Unit to identify people who have overstayed their visas or are in the United States without proper authorization. The LeadTrac system includes biographical information on potential immigration violators as well as information on associates or relatives; it also includes passports or driver’s licenses data, border crossing histories, criminal records, and immigration history, State Department and Department of Justice records, student visa files, academic histories, and biometric information kept by DHS. LeadTrac also contains extensive records on organizations such as schools or universities regarding their role in sponsoring immigration applicants. LeadTrac also references the controversial NSEERS database, which was discontinued in 2011 by the Obama administration. The data from NSEERS was never purged.


ICEPIC is a pattern analysis tool that searches for relationship patterns among individuals and organizations that could reveal immigration violators or potential terrorist plots. The tool draws on law enforcement records and third-party commercial databases, student visas, the NSEERS list, immigration records, the terrorist watchlist.

What Cities Are Doing

While sanctuary cities cannot prevent federal agencies from accessing their criminal and non-criminal data, and the range of data that ICE can access is daunting, there are concrete steps being taken by some municipalities to safeguard data on residents.

“The only way information is not going to get to ICE is to not collect it,” said Muniz, the UC Irvine professor. “These systems, as they’ve been fractured, have been recording information centered around encounters,” Muniz said. “ICE is now trying to make these systems person-centered, to use tools to go through and delete any duplication through biographic or biometric information.”

Muniz is currently studying the federal government’s data mining practices over the past few decades, and has observed the influence information-gathering practices has had on ICE’s field operations and their relationships with local law enforcement. “Historically, the feds have tried to involve local police and sheriffs as force multipliers through agreements like 287(g),” Muniz said, referring to a Clinton-era program to deputize cops as immigration agents that was widely abandoned by the Obama administration but is now in favor under Attorney General Jeff Sessions. “Now, they don’t really care about having extra bodies, ICE only wants the data.”

“The best thing that cities can do is not collect certain info or get rid of it as soon as they don’t need it anymore,” said Kade Crockford, the director of the Technology for Liberty program at the American Civil Liberties Union of Massachusetts. Crockford said that while Boston is a self-identified sanctuary city and has vowed to stay the course, one of the easiest steps the city could take would be to stop arresting people for “quality of life” offenses, thereby keeping their fingerprints out of federal databases like the FBI’s NCIC that ICE has access to. “It’s the fingerprinting that’s the problem — it is the easiest and most dangerous way for ICE to become aware of people who are undocumented,” Crockford said.

Similarly, community organizers in New York City have turned the dialogue around broken windows policing towards police interactions with undocumented residents. The argument advocates make is that immigrants will pull back from authorities if they believe interacting with the government on any level could result in deportation. Josmar Trujillo, an East Harlem organizer, spoke on a panel about ICE and sanctuary cities at CUNY Law School in Queens last month. Trujillo said that if immigrants realize their contacts with police or their applications for municipal identities cards could make them targets for ICE, undocumented residents will pull back from civic life. “My mother came into this country in the trunk of a car — she taught me to avoid all contact with the system,” said Trujillo. “You don’t want to start creating a de-facto registry of undocumented folks or hoover up information on people through low-levels charges, specifically because of an event like the Trump election.”

On a policy level, some of the most concrete steps to decouple local government and law enforcement from immigration authorities have taken place in the West. In February, Gov. Jay Inslee of Washington state issued an executive order barring any state or local agency from arresting people for violations of immigration law. In California, as San Francisco and Santa Clara County fight to block Trump’s executive order on sanctuary cities in federal court, the state Senate approved SB 54, a bill that would bar any law enforcement or government agency from providing information or resources to assist federal agencies enforce immigration law.

Not all states are in line with California. Both houses of the Texas legislature approved SB 4, a bill championed by Gov. Greg Abbott that will withhold state funding from cities that refuse to cooperate with ICE. Similar laws were passed by state legislatures in Arizona, Georgia, and Tennessee during the Obama administration.

Adam Schwartz, a lawyer with the Electronic Frontier Foundation, has been involved in the writing and lobbying around SB 54. “Government agencies are surfing on oceans of data,” Schwartz said. “Under this law, the norm is that data doesn’t get commandeered for purposes of immigration enforcement.”

While California’s SB 54 has received pointed criticism from Sessions as well as state and Congressional Republicans, the bill has been amended to allow ICE access to the California Law Enforcement Telecommunications System, which allows access to records from police departments and courts throughout the state.

On a local level, some cities have started to pull back from federal task forces. In January, San Francisco ended its police department’s participation in the local Joint Terrorism Task Force, over concerns that the FBI-led unit would unlawfully target Muslims. In Oakland, a government committee responsible for policy-making on surveillance issues is reviewing the police department’s participation in the JTTF and a Homeland Security Investigations Task Force.

The uncertainty around the extent of the federal government’s ability to compel local governments to enforce immigration law and the wide variance in state laws about sanctuary policy mean that, for the time being, local and state policies will determine where undocumented residents receive the greatest deal of protection from ICE. California’s attempt to restrict ICE’s access to state data will prove a turning point if SB 54 becomes law, but there is a high likelihood that the Trump administration will seek redress in the courts.

This article was reported in partnership with The Investigative Fund at The Nation Institute, now known as Type Investigations.