The Gregorio brothers had just begun their daybreak commute to work assembling wooden pallets in late January when federal officers in SUVs pulled them over in a Chicago suburb. Jhony and Bayron were in one car. A third brother, Marco, was traveling separately, in another car behind them.

After Jhony Gregorio handed over his identification, an officer with Immigration and Customs Enforcement opened his door and pulled him out. Before long, more than a dozen other officers had arrived. Gregorio could see they had also stopped his brother Marco.

All three had been living and working in the United States without authorization after arriving from Guatemala. None had criminal records. But Bayron Gregorio had received a deportation order. Instead of detaining only him, authorities took all three brothers into custody.

Attempting to fulfill a campaign pledge to deport millions of people, the Trump administration has turned to tactics that have prompted a flurry of court challenges across the country and created an atmosphere of fear. Each week has brought a new example, as agents have detained immigrants and shuttled them out of the country to Guantanamo Bay, Cuba; Panama; and, most recently, a dangerous prison in El Salvador without hearings, much less opportunities to communicate with lawyers and relatives.

But in Chicago and other cities, there are quieter operations underway that raise similar legal questions as federal agents pick up people in ones, twos and threes.

Lawyers for Jhony and Marco Gregorio are arguing that their arrests were among at least 22 that violated a court settlement prohibiting authorities from detaining undocumented people they coincidentally encounter while serving warrants for others. So-called collateral detentions were the subject of a 2022 class-action settlement that set out stricter parameters for how agents should handle these situations, including new restrictions on warrantless arrests.

Attorneys for the Trump administration have denied allegations that the arrests occurred in violation of that agreement, called Nava, after one of the original plaintiffs. Specifically, administration lawyers argued the arrests were not warrantless, according to court records.

Under the Nava settlement, ICE agents are required to adhere to strict guidelines to make warrantless arrests, including establishing that someone will attempt to flee instead of participating in court proceedings.

“The administration’s approach to immigration enforcement and how it has responded to court orders was bound to be the canary in the coal mine of this administration’s overall approach to our democracy and the rule of law,” said Mark Fleming, associate director of litigation at the National Immigrant Justice Center, which is representing Jhony and Marco Gregorio and other detainees as the center goes to court alleging Nava settlement violations.

Observers and advocates say they don’t expect the White House to let up on its crackdown or adjust its tactics because of any legal pushback.

“I don’t think they back down,” said Kathleen Arnold, DePaul University professor of refugee and forced migration studies. “They assumed that there weren’t due process roadblocks that could prevent ICE from doing exactly what they want.”

Neither ICE nor the Department of Homeland Security responded to requests for comment.

During the initial roundups in January, the administration made it clear that collateral arrests were part of strategy for enforcement in Chicago and other sanctuary cities where local law enforcement declines to assist in migrant arrests. “There’s going to be more collateral arrests in sanctuary cities because they forced us to go into the community and find the guy we’re looking for,” White House border czar Tom Homan told reporters in a televised interview.

The stricter arrest guidelines from Nava were adopted as national policy under the Biden administration, attorneys for the plaintiffs said, but were rescinded after Trump entered office in January. The agreement remains in effect in Illinois, Indiana, Kansas, Kentucky, Missouri and Wisconsin, all states covered by the Chicago ICE office, the attorneys said. It’s set to expire in May.

Attorneys for National Immigrant Justice Center and ACLU of Illinois this month went to court in Chicago citing the Nava settlement and seeking an order that the federal government stop creating warrants in the field, reimburse their clients for bond costs and provide weekly reports of any warrantless arrests. They also are asking for the release of the two clients identified in the suit who are still being held.

In making the argument that ICE and Homeland Security are violating the Nava settlement, attorneys for the two Gregorio brothers said Jhony and Marco clearly were not flight risks. They both have been living in the U.S. for over a decade and have ties to the Chicago area and suburban Maywood, where they live. Jhony Gregorio is married and has a child who was born in the U.S.

The only warrants for them, the attorneys said, were written up after they were detained.

“The creation of a warrant after the fact does not cure the warrantless nature of these incidents,” attorneys for the plaintiffs wrote, “and the Settlement’s training material specifically forbid reliance on post hoc administrative warrants to avoid warrantless arrest requirements.”

In the end, the two brothers and most of the other migrants cited in the lawsuit were released and able to remain in the United States, at least for now. Two of the 22 still are in ICE custody, and one has been deported, lawyers for the two advocacy groups said.

Jhony and Marco Gregorio now face an immigration case that could see them removed from the United States. Attorneys for the pair are not claiming that ICE’s arrest of their brother, Bayron, was unwarranted, and he is not a party in the lawsuit. It is unclear if he’s been deported.

Among those released is Julio Noriega, a 54-year-old Chicago man. He was handing out resumes to local businesses in search of work when he was approached by ICE officers in January, according to his witness declaration in the latest Nava filings.

Before he had a chance to explain, Noriega said, the officers placed him in handcuffs and moved him into a van. It wasn’t until after he’d already been taken to an ICE processing center and waited several hours that officers checked his wallet and realized he is a U.S. citizen.

Abel Orozco-Ortega, 47, who is also named in the new Nava filings, was arrested in January, too. He’d just returned home from buying breakfast for his family when officers detained him outside his house in Lyons, a suburb of Chicago where he’s lived with his family for the last 15 years.

Federal agents were looking for Orozco-Ortega’s son. They didn’t find him but took Orozco-Ortega into custody. Orozco-Ortega said in his statement that he has no criminal history. Filings in his case do not detail why agents were looking for his son. Orozco-Ortega has been residing in the U.S. without authorization.

His wife, Yolanda, said he is no criminal and pleaded for his release. “He doesn’t have any vices, he doesn’t do drugs, he goes to church,” she said speaking through an interpreter at a recent press conference. “Is it a crime to get up early every day for work to support your family? I just don’t know.”

Fleming said the center is continuing to compile examples of arrests that the firm believes show warrantless arrests.