BOSTON (AP) — A Massachusetts prosecutor is backing an effort to prevent federal authorities from arresting immigrants targeted for deportation at courthouses.

Middlesex District Attorney Marian Ryan said in a letter to Justice Elspeth Cypher of the Supreme Judicial Court on Monday that she’s concerned the prospect of courthouse immigration arrests will have a “hugely detrimental effect” on law enforcement.

Civil rights and indigent defense groups filed a petition with the court last month that seeks to bar officials from making immigration arrests at courthouses.

Ryan is urging Cypher to report the petition to the full court for review. She said in her letter that the case has “grave implications for the fair and effective administration of justice.”

The Boston Bar Association has also asked for a full-bench review.

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