BOSTON (CBS) – The 18 protesters arrested after a demonstration outside the ICE detention center in Dorchester Tuesday evening won’t be prosecuted, a spokeswoman for Suffolk County District Attorney Rachael Rollins said.

The protest against the Trump administration’s immigration policies and migrant camps at the border lasted for hours. A crowd of hundreds walked from the Holocaust Memorial to the detention center located at the Suffolk County House of Corrections, where the arrests happened.

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Hundreds walked from the Holocaust Memorial to the ICE detention center in Dorchester to protest migrant detention center conditions (WBZ-TV)

“All 18 individuals appeared this morning in Roxbury Municipal Court, where Suffolk prosecutors filed a nolle prosequie prior to arraignment in each of their cases,” spokeswoman Renee Algarin said in a statement Wednesday. “This filing formally ends prosecution in each case.”

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The arrested protesters had all been charged with trespassing. None had prior criminal convictions. The district attorney’s office said that the decision not to prosecute is in accordance with Rollins’ and her predecessors’ handling of similar offenses.

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“The protesters’ peaceful challenge of the inhumane detention policies of the Trump administration is protected by the First Amendment,” Rollins said.

Boston Police guided the protesters the entire way. While there were no major issues, there was some additional traffic as the crowds passed through.

“Say it loud, say it clear: immigrants are welcome here,” they chanted at one point.

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Rollins has been critical of ICE and won a legal victory in a lawsuit she filed last month when a judge temporarily blocked immigration agents from making civil arrests at Massachusetts courthouses.