The fender bender seemed inconsequential.

Claudia Ramos’s vehicle was struck from behind in Hyattsville , Md., as she drove her youngest child to day care. It was more shocking than damaging, she said.

Then someone called the police.

Ramos waited for the Prince George’s County officer who responded to produce a crash report. As the minutes ticked into an hour, she called a relative to pick up her three children. The other drivers left, but the officer told her to stay.

An unmarked vehicle arrived, and a U.S. Immigration and Customs Enforcement officer approached. “Do you have papers?” Ramos recalled the officer saying. She was taken into federal custody.

Ramos is one of at least three undocumented immigrants placed in deportation proceedings recently after contact with police in Prince George’s, a Maryland suburb that has promised not to cooperate with federal immigration enforcement efforts and to offer a welcoming community for its estimated 80,000 undocumented residents.

“I didn’t think it could happen here,” Ramos said in an interview.

Top officials in Prince George’s say they didn’t think so either.

Police Chief Hank Stawinski blamed the arrests on confusing language in the FBI national criminal database, which he said makes it hard to distinguish between an “outstanding administrative warrant of removal” — a civil document similar to a court subpoena — and a criminal arrest warrant.

Police in Prince George’s generally are not supposed to act on the civil removal notices, which are considered federal matters and can compromise the ability of local officers to work effectively with immigrant residents.

But Stawinski said officers who ran names through the FBI’s National Crime Information Center database and got a hit for a “warrant” sometimes ended up contacting ICE anyway, believing there was a criminal charge pending.

Immigration lawyers say similar issues frequently have arisen in other “sanctuary” jurisdictions, including Baltimore County, where the American Civil Liberties Union sued the police department in 2014 over cooperation with ICE. No one has effectively tracked how many immigrants have been transferred to ICE in sanctuary cities and counties, however, in part because immigration records are secret.

“If you don’t train your officers on the differences, they will think that they have to call immigration,” said Angelica Salas, executive director of the Coalition for Humane Immigrant Rights in California, which passed a law in 2017 limiting the use of state resources in immigration enforcement.

With a growing number of local jails refusing to honor ICE detainers, she added, routine traffic stops have become “one more tool” for the federal government “to detain and deport people.”

Prince George’s had long said its police officers would not work with federal immigration agents on civil deportation proceedings, but those policies did not exist in writing, officials said.

After The Washington Post inquired about the arrests of Ramos and others, County Executive Angela D. Alsobrooks (D) and Stawinski sought explicit rules barring cooperation with ICE on noncriminal matters. The policies are being finalized this week, officials said, and a video of Stawinski explaining them will be circulated among police officers and the immigrant community in coming days.

“In Prince George’s County, our law enforcement does not and will not do the work of a federal agency,” Alsobrooks said.

Stawinski said his officers “were acting in good faith, and I believe they thought they were serving a criminal warrant. . . . If it’s criminal, we will serve it. If we are looking at a civil warrant, we don’t serve them.”

Immigration advocates applauded the new rules for police. But they said a parallel policy for the county Department of Corrections was a step backward because it requires jail officers to alert ICE about undocumented prisoners with deportation orders if they have criminal records or have been charged with certain offenses, including “criminal gang activity.”

An expanding database

The revised policies are being rolled out at a time of stepped-up immigration enforcement and growing anxiety among the country’s estimated 10.5 million undocumented immigrants.

But immigration attorneys and advocates say many local law enforcement agencies — including those with sanctuary-like policies — have assisted in immigration enforcement for years, in part because of changes to the FBI database made after the attacks of Sept. 11, 2001.

The database had been restricted to criminal warrants and a limited number of civil warrants for noncitizens with felony convictions, which were permitted by Congress. Then the office of Attorney General John Ashcroft opined that local police have the power to make immigration arrests. The FBI and Department of Homeland Security subsequently placed nearly 500,000 civil warrants into the NCIC system, said Mark Fleming, chief litigation coordinator for the National Immigrant Justice Center.

The Supreme Court rejected the opinion a decade later. But the civil orders have not been removed, despite repeated calls to do so by , among others, the Major Cities Chiefs Association, which represents police chiefs and sheriffs from dozens of large cities.

“They’ve kind of entrapped local law enforcement,” Fleming said.

Darrel Stephens, interim executive director of the chiefs association, said the civil orders expose police departments to liability, and the legal basis for them is uncertain.

ICE officials did not answer specific questions about the civil orders. But agency spokeswoman Justine Whelan said in a statement that “cooperation and information sharing amongst law enforcement agencies at every level remains the gold standard to ensure collective public safety nationwide.”

“Our officers comport themselves with professionalism, and data is shared accurately and carefully, without intending to ‘fool’ anyone,” Whelan said.

A bill proposed in Annapolis two years ago would have clearly defined Maryland as a sanctuary state in language akin to that adopted by California, Connecticut and a handful of others. The bill passed the House but failed in the Senate.

Since then, a number of municipalities and counties — including at least eight towns and cities in Prince George’s — have enacted policies that prevent police from helping ICE on civil matters. Montgomery County and the District of Columbia, which border Prince George’s, have explicit general orders barring cooperation with federal immigration efforts as well.

Prince George’s County Council member Deni Taveras (D-Adelphi) said she will introduce a bill in the fall codifying the new police policies, limiting the government’s authority to arrest or detain without a judicial criminal warrant and prohibiting anyone from asking about a person’s immigration status.

It is not clear how such a law would affect the revised corrections policy, a response to ICE’s criticism of Prince George’s after the MS-13-related slaying of a 14-year-old girl in April.

Two of the suspects in that killing were arrested in the county a year earlier on gang-related attempted murder and robbery charges. ICE asked detention officials to alert agents before their release so they could be arrested and deported.

But the jail did not flag ICE when Joel Escobar was freed in March because he had pleaded guilty to conspiracy to commit robbery, a nonviolent offense. Had the new policy been in place, the jail would have notified ICE, county officials said, because Escobar, then 17, was also charged with a number of violent crimes. Those charges were dropped as part of the guilty plea.

Alsobrooks said the new jail policy is about keeping the community safe: “We don’t want people to feel under siege here. The vast majority of our immigrant community are law-abiding people.”

She said people charged with or convicted of violent or gang-related crimes, “be they immigrant or not immigrant, these are people we don’t want in our community.”

A traffic stop, then handcuffs

Ramos, who was detained after being rear-ended, crossed the border illegally in 2005 and has lived in the District since then, working in a downtown hotel. An immigration judge issued her final deportation in 2005 after she failed to show up for a hearing. Ramos said she was unaware of that court date and the deportation order.

When she was arrested Feb. 14, she was held for about a day, then released. Her attorneys are trying to reopen her immigration case.

Jose Roberto Ortega of Temple Hills and Maria Pérez Baires of Hyattsville were each taken into ICE custody last year after Prince George’s police stopped them for traffic infractions.

Ortega was driving to his landscaping job in March 2018 when he made an illegal U-turn and received a $90 ticket, court records show. An ICE agent arrived moments later and put Ortega in handcuffs. By May 23, he was deported to El Salvador, leaving behind a 16-year-old son who had joined him in the United States a year earlier.

“I came here to be with my father,” said Jose Roberto Montero, who is seeking permission to stay in the United States through a program known as special juvenile immigrant status. “Now, we are separated again.”

Pérez Baires, a single mother of two who is also Salvadoran, was stopped in May 2018 for speeding. After she was detained, ICE agents told her to buy a plane ticket home, where her abusive ex-husband was waiting.

“Who would take care of my boys?” she said in an interview. “They have no one else.”

She was released hours after her arrest with an ankle monitor.

Her attorneys, Katie Hutchison and Abdoul Konare, argued successfully to have her case reopened, based on her history of experiencing domestic violence and the danger she would face in her country of origin.

“Maria’s case is not an aberration and not an exception,” Konare said. “We have clients all over . . . who have been stopped for having a broken taillight or some other minor issue and ended up with ICE. Children were left behind. People were put back in danger. Police should know by now what they are doing.”

Lynh Bui contributed to this report.