A report by the ACLU of Maryland says a federal policy that requires immigrants with certain criminal convictions to be detained without bond while they wait for their cases to be heard is excessive and costly. (Steve Ruark/AP)

A federal policy that requires immigrants with certain criminal convictions to be detained without bond while they wait for their cases to be heard is excessive, costly and has resulted in lengthy and unnecessary detentions of immigrants in Maryland, according to a report by the American Civil Liberties Union of Maryland.

In a report released Thursday, the ACLU said that the practice of mandatory detention has had “draconian consequences” for many immigrants who ultimately won their cases after months in detention.

“The current system of mandatory detention is heavily stacked against immigrants who have never made any mistake, and unnecessarily and unlawfully results in the detention of many who should be eligible for bond,” said Sirine Shebaya, a writer of the study and a former attorney at the ACLU. “Excessive use of no-bond detention appears designed to discourage people from pursuing their cases, because fighting a court battle while detained for long periods of time becomes too difficult and unbearable — even for those with strong challenges to deportation.”

A spokeswoman for U.S. Immigration and Customs Enforcement said she could not comment until she reviewed the report.

The findings on mandatory detention in Maryland mirror what is happening across the country, Shebaya said. “This is pretty consistent . . . with what advocates say they are seeing,” she said.

There are 34,000 immigrant detainees being held on any given day across the United States, according to the report. The total — which includes all immigrant detainees, not just those in mandatory detention — reached a high of almost 478,000 in 2012.

The report, which was also written by Robert Koulish, a government and politics professor at the University of Maryland, tells the stories of six detainees. The report reviewed 96 cases of immigrants detained without bond.

Among them are: a man in Prince George’s County who had been convicted of a minor drug offense 20 years ago; a Montgomery County man convicted of a minor theft offense; and a woman — who is a permanent resident and has two U.S.-born children — who had been convicted of two minor shoplifting offenses.

Shebaya and Koulish questioned the use of mandatory detention in these cases. Each of the detainees “almost certainly” would have been released on bond if it were offered, they said, and noted that several of them posted small bonds for their criminal charges and never missed a court date.

“Many never faced any jail time for their crime,” the report says. “All had strong immigration cases, and none posed a danger to the community or a risk of flight. Yet each was held in immigration detention for months or years until the resolution of their cases, without having an opportunity to make a case for their release.”

Shebaya and Koulish said they hope the report demonstrates that many who are being held without bond are not dangerous offenders and that it leads to changes in the law.

Their initial interviews were done in early 2015. By the release of the report, four of the six detainees had won their immigration cases and returned to their families. One obtained an administrative closure of his case after two years in detention, and the other was deported.