LOS ANGELES (AP) — Immigrant advocates filed a lawsuit Wednesday over concerns that federal immigration agents could use state driver’s license databases to track down people for deportation.

The National Immigration Law Center sued the Department of Homeland Security demanding documents detailing how federal immigration agents access and use driver’s license data.

The lawsuit comes after immigrant advocates in Maryland received reports that federal agents earlier this year arrested several immigrants with prior deportation orders after apparently identifying them with help from a driver’s license photo and vehicle information.

It also comes about two weeks before California starts issuing driver’s licenses to immigrants in the country illegally. More than 1 million people are expected to apply over the next three years.

“We need to at least know what the current policy is,” said Melissa Keaney, an attorney at the Los Angeles-based advocacy organization. “We don’t want to cause unnecessary panic, but we don’t want to cause a repeat of what happened in Maryland.”

The lawsuit aims to compel Homeland Security and Immigration and Customs Enforcement to release records under the Freedom of Information Act that were requested in April.

ICE declined to comment on the suit. The agency does not use driver databases to identify immigration enforcement targets but “like other law enforcement agencies, ICE may use DMV data in support of ongoing criminal investigations or to aid in locating individuals who pose a national security risk or public safety threat,” said Gillian Christensen, an agency spokeswoman.

Ten states have approved driver’s licenses for immigrants in the country illegally, many of them with a distinct marker so the documents can be distinguished from those carried by U.S. citizens and permanent residents. Meanwhile, a ruling by the U.S. Supreme Court on Wednesday has moved thousands of young immigrants a step closer to obtaining driver’s licenses in Arizona.

In California, advocates have long raised concerns about privacy protections for immigrants applying for the new licenses, fearing the information could be used by law enforcement agencies that have access to driver data for investigative purposes.

The Center argues more information is needed about how immigration enforcement agents use driver data to dispel any concerns that might discourage immigrants from applying for driver’s licenses.

A message was left for California’s Department of Motor Vehicles seeking comment.

After the Maryland arrests, state officials there told immigrant advocates that federal immigration officials can query the database by name but can’t execute a bulk download, said Elizabeth Alex, lead organizer for CASA de Maryland.

Alex said she was surprised to learn of the arrests after Maryland resumed issuing driver’s licenses to immigrants in the country illegally.

“We started getting a lot of questions from people saying, ‘Is it safe?”’, she said, adding that the group has been encouraging immigrants with a deportation record to seek legal advice before applying for a license.

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