When U.S. Homeland Security agents requested local help in a major gang bust, Santa Cruz County Sheriff Jim Hart was hesitant.

He was happy to send deputies to break up a gang, but didn’t want them to assist in the arrests of people whose only offense was being in the country illegally. So he requested plans for the operation, and when he didn’t get the information he needed, he steered clear. Police in the city of Santa Cruz had been involved in the investigation for five years and joined in the Feb. 13 raids.

“I obviously follow national politics, and I saw the large number of immigration raids,” Hart said. “My initial impression was there may be more to this story than what I’m being told.”

The sheriff’s fears were realized when Homeland Security Investigations, known as HSI, swarmed Santa Cruz and arrested not just alleged MS-13 members but others suspected only of immigration violations — actions known as collateral arrests. The Santa Cruz Police Department soon apologized for participating, and what could have been a visible victory in the fight against a notorious gang became, at least in part, a symbol of something else.

There’s a fundamental divide between HSI, whose 6,200 agents do critical work, and many police forces in the Bay Area and beyond — one that could stall cooperation on investigations of gangsters, sex traffickers and other criminals.

Back to Gallery ‘Collateral’ immigration arrests threaten key crime... 3 1 of 3 Photo: Gabrielle Lurie, The Chronicle 2 of 3 Photo: Gabrielle Lurie, The Chronicle 3 of 3 Photo: Gabrielle Lurie, The Chronicle





HSI, a division of U.S. Immigration and Customs Enforcement, or ICE, is now mandated to make collateral immigration arrests of nontargeted individuals found at the scene of operations, according to a Homeland Security source, while many police officials said in interviews that they will refuse to cooperate if such arrests are on the table.

“It creates a wedge because local law enforcement wants to cooperate on human smuggling, child pornography and narcotic cases, but at the same time they need to have the trust of their local communities,” said George Gascón, the district attorney of San Francisco. “Striking that balance there becomes very difficult.”

Asked in an interview this month whether HSI agents were mandated to make collateral arrests, Ryan Spradlin, the agency’s special agent in charge in San Francisco, said executive orders signed by President Trump had changed his agents’ ability to use “discretion” on the ground to not make arrests. But he said they still made case-by-case determinations.

What Santa Cruz leaders did not know before the February raids is that they were on the front lines of a big shift in policy under Trump. Having HSI agents make collateral arrests gives the administration an instant way to boost the number of federal agents making immigration arrests, which is consistent with priorities laid out in executive orders.

Currently, there are more HSI agents than the 5,800 deportation officers within ICE, according to a 2016 budget brief.

It adds up to a dilemma for HSI, the largest investigative arm of Homeland Security with 26 offices around the country. The agents work separately from their ICE counterparts, and they’ve generally avoided immigration-only arrests during operations in California — though they’ve always had the discretion to make them.

“If HSI has shifted or expanded its mission ... you have effectively doubled immigration enforcement officers in the U.S.” said Pratheepan Gulasekaram, an immigration expert and professor at Santa Clara University School of Law. “That is a significant increase without having to seek another congressional appropriation.”

Moreover, the new mandate threatens a fruitful, if fragile, relationship the agents have with Bay Area authorities who in many cases are actively seeking to assure their communities they are not in the business of immigration enforcement. They say they want to make sure undocumented immigrants feel safe reporting crimes, sending their children to school and accessing health care.

HSI targets “cross-border criminal activity” and organizations that exploit “America’s travel, trade, financial and immigration systems,” according to its own materials. The group is key in the fight against MS-13, or Mara Salvatrucha, which has operated in Los Angeles, San Francisco, Mexico, Central America and many other places.

“The Department of Justice has the Federal Bureau of Investigation, and the Department of Homeland Security has Homeland Security Investigations,” Spradlin said. “We are in the business of public safety and national security, and a lot of folks don’t know that.”

HSI works at times with local agencies on wide-ranging criminal investigations. In the past, the balance worked — cities like Santa Cruz simply did not have the resources to conduct complicated, international investigations involving community troublemakers, while their federal partners needed city police for their local knowledge.

In the Bay Area in recent years, joint investigations have yielded major busts, including of a sex-trafficking ring in Emeryville. HSI, local and state authorities said they discovered a massage parlor that was actually a brothel, exploiting young women and replacing them every few weeks. Joint operations have also led to the seizure of $39 million in counterfeit sports-related items, and numerous child-pornography cases.

Spradlin said the Santa Cruz raids had not seriously hurt HSI’s relationships with local agencies. While Santa Cruz police officials said recently that an HSI agent could no longer keep a desk at the department, they noted that they would continue to work with the agency.

Local partners are anxious about immigration arrests, Spradlin said, but the arrests are legal and proper. He said it was important for the agency to be “open and candid” as to what would happen on the ground in the operations.

“At the end of the day, it is against federal law,” he said of immigration violations. “We don’t make the determination as far as what’s law and what’s not.”

But around the Bay Area, leaders of police departments and sheriff’s offices said they will look for assurances from HSI — perhaps asking for written agreements spelling out that secondary immigration checks will not happen.

“We do not want to be a part of any law enforcement agency that is indiscriminately, in the wake of a felonious arrest, taking people to jail only for an immigration violation,” said San Rafael Police Chief Diana Bishop, whose city has a large community of Latino immigrants. “We can’t be a safe city without people trusting their police — a relationship we’ve really tried to build over the years.”

Police Chief Allwyn Brown of Richmond, which also has a sizable immigrant community, said that what happened in the Santa Cruz operation would “make it more difficult for the agency to get cooperation in the future.”

After the Santa Cruz raids, more than a dozen law enforcement agencies in Santa Clara County, including the San Jose police force, released a letter saying they would not assist in immigration arrests.

In San Francisco, police are “prohibited from enforcing or assisting (federal agents) in enforcing immigration laws,” said Sgt. Michael Andraychak, a department spokesman.

Professor Gulasekaram said local agencies have a difficult choice to make about the nature of their relationship with immigrant communities. And indeed, in Santa Cruz, the fallout from the gang operation was significant. At a City Council meeting in late February, Jose Lucas, a resident of the city for 16 years, stood up and told the assembly that his daughter had been arrested in the operation.

She was one of 11 people arrested for immigration-only offenses, while 10 alleged MS-13 associates were snagged.

“Her only crime is to be here illegally,” he said. He said he would no longer trust police in the city because “they arrested people that hadn’t done anything wrong, just because they were in those homes. ... Now, we drive in fear when a cop is driving behind us.”

While Santa Cruz strengthened its sanctuary laws after the raids, the Trump administration called out the city for its reaction to the operation.

In a letter warning nine communities with sanctuary laws that they were at risk of losing federal funding, the Justice Department said Santa Cruz leaders “seemed more concerned with reassuring illegal immigrants that the raid was unrelated to immigration than with warning other MS-13 members that they were next.”

Santa Cruz Mayor Cynthia Chase called the conflict “psychologically damaging.”

“It created a ripple effect of fear and mistrust,” she said, “and that’s something that’s going to take us a while to recover from.”

Hamed Aleaziz is a San Francisco Chronicle staff writer. Email: haleaziz@sfchronicle.com Twitter: @haleaziz