It was late March when Joe Teirab, the second-in-command at Minnesota’s U.S. attorney’s office, received an urgent email from Washington.

The federal government was scrambling to find criminal cases to back up President Donald Trump’s claims that illegal voting by noncitizens was tipping the scales in American elections. Agents from Homeland Security Investigations, a massive federal law enforcement agency, had been dispatched to work leads across the country, including hundreds in Minnesota.

Teirab was already under pressure. In an earlier missive, Nick Davis, a high-ranking Justice Department appointee helping to lead the election fraud crusade, had reminded him the cases were so high priority that Teirab and his staff couldn’t decline to move forward on them without express approval from agency higher-ups. On March 24, Davis demanded a status report — within hours.

Teirab, a former Marine and a Harvard Law graduate who’d run unsuccessfully for Congress as a Republican, responded with a blunt reality check.

“Bottom line up front,” he replied in an email reviewed by ProPublica. After subpoenaing records on about 130 people, only one had been referred for prosecution, his staff had told him. Agents had deluged local election offices with calls and demands for voting histories, demonstrating “a complete lack of understanding” of illegal voting investigations.

“The HSI task force has been disjointed and disorganized,” Teirab wrote. The entire process, he said, had been “dysfunctional.”

Since Trump regained the White House, his administration has launched a series of unprecedented initiatives to find and prosecute voting by noncitizens, which he’s long claimed, without evidence, is rampant.

He’s stepped up this push in recent weeks, saying in a nationally televised speech that the American election system was “so vulnerable that no one can possibly defend it.” To support that assertion, the Department of Homeland Security, HSI’s parent agency, released documents asserting it had found more than 250,000 noncitizens on voter rolls in just four states, all led by Democrats. The documents included no explanation of how that number was calculated.

It’s well known the administration has tasked HSI — a force established to combat drug cartels, terrorism and other cross-border criminal enterprises — with leading the campaign to find election fraud cases in the United States.

But an investigation by ProPublica reveals for the first time how the Trump administration came to harness HSI’s personnel, technology and sweeping legal authority in service of its election agenda — and how meager the results have been, despite the prodigious resources sunk into the effort.

According to interviews and internal emails reviewed by ProPublica, career staffers at the Justice Department warned that transferring voter rolls to HSI to enable it to search for noncitizen voters could violate federal privacy laws. Similarly, longtime HSI insiders cautioned that using the agency’s databases and tools to search these lists would yield mismatches and wildly inflated results.

The administration plowed forward anyway.

We are continuing our reporting on how the Trump administration has enlisted HSI agents and technology in unprecedented ways to enforce immigration laws and to bring cases against suspected noncitizen voters. Do you work at HSI and have information you can share with us? You can reach our tip line on Signal at 917-512-0201, or you can contact Peter Elkind at peter.elkind@propublica.org or on Signal at 817-691-3110. Please be as specific, detailed and clear as you can.

HSI’s involvement in the hunt for election fraud traces at least to summer 2025, when agency supervisors embraced a proposal from a midlevel agent who’d publicly echoed Trump’s claims about elections. He argued the agency’s powerful databases and tools could find noncitizens even on the voter lists that states make publicly available, from which the most confidential information has been redacted. Under Trump, the Justice Department had collected many public voter rolls as part of a controversial effort to compel states to turn over the unredacted versions.

Those searches went forward, ProPublica’s reporting shows, helping to generate tens of thousands of leads regarding illegal voting across the country. But when HSI agents were sent to investigate them, the results were similar to what Teirab reported from Minnesota.

Between January 2025 and May 2026, a ProPublica analysis of Justice Department data shows, fewer than 150 alleged noncitizen voters were referred for prosecution. Even fewer — 41 — were charged with voting illegally or other election-related crimes. (More than 150 million people voted in the most recent presidential election.)

In response to questions from ProPublica, administration officials insisted the effort spearheaded by HSI was producing meaningful results.

“President Trump is committed to ensuring that Americans have full confidence in the administration of elections, and that includes totally accurate and up-to-date voter rolls free of errors and unlawfully registered non-citizen voters,” Abigail Jackson, a White House spokesperson, said in response to ProPublica’s request for comment. “Noncitizens voting is a crime. Anyone breaking the law will be held accountable.”

A DHS spokesperson didn’t answer questions about why so few prosecutions have resulted from HSI’s work. The agency wouldn’t specify what tools or techniques HSI had used, but confirmed it had cross-referenced “publicly available data” from state voter rolls with information on “known illegal aliens” in its systems. “It’s not rocket science,” the spokesperson wrote of this initiative in a response to ProPublica’s questions. “It’s an easy step to secure our elections.”

Teirab and the U.S. attorney’s office in Minnesota declined to comment.

There’s an array of reasons why Trump’s campaign to document claims of widespread voter fraud hasn’t succeeded. Most obviously, it’s exceedingly rare, as countless studies and state audits have found. Noncitizens often get on voter rolls by accident or when government officials make errors. Last month, New Jersey disclosed that a mistake involving its Motor Vehicle Commission caused 6,600 noncitizens to be registered (fewer than 400 voted).

The administration’s critics say its hunt for noncitizen voters aligns with Trump’s attempts to seek more federal control over elections while stoking doubt and fear about the voting process. Since taking back the Oval Office, Trump has tried to impose new restrictions on voter registration, mail-in ballots and voting machines, though judges have shut down most of these efforts.

Former officials at DHS and the Justice Department called the move to involve HSI a further escalation and questioned the propriety of aiming the agency’s muscle and technology at individual cases of illegal voting.

“It’s one thing if you’re going after Pablo Escobar,” said Steve Bunnell, a former DHS general counsel and senior intelligence adviser who handled voting fraud prosecutions during more than a decade at the Justice Department. “It’s another thing if you’re going after some cleaning lady who’s been working in the United States for 20 years and taking care of her 80-year-old mother and taking her little kids to church.”

“The Swiss Army Knife of Federal Law Enforcement”

Trump’s enlistment of HSI in his election fight is no accident. Cobbled together in the aftermath of 9/11, the agency has 7,100 armed, highly trained agents and another 800 criminal analysts, as well as access to troves of confidential data about hundreds of millions of Americans.

Though part of Immigration and Customs Enforcement, the agency has historically stayed out of immigration cases. During the first Trump administration, leaders of 19 HSI regional offices — virtually its entire top field hierarchy — signed a letter calling for HSI to become a standalone agency, arguing that ICE’s deportation work dissuaded people from cooperating with its investigations. But when Trump returned to the White House, it swiftly became clear that the agency would play a central role in investigations related to the president’s twin obsessions, illegal immigration and noncitizen voting.

Trump picked his field general for repurposing HSI even before taking the oath of office. In December 2024, he named Anthony Salisbury, a 50-year-old career agent who’d run the........

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