Chicago’s top federal prosecutor dismissed the remaining charges against four activists who protested outside a federal building during last year’s immigration crackdown, after a judge examined allegations of grand jury misconduct by the prosecutor’s office, according to court proceedings described by the Associated Press.

U.S. Attorney Andrew Boutros announced the dismissal on Thursday in court following a closed-door meeting tied to redacted grand jury transcripts, the AP reported. Perry had been reviewing claims that prosecutors improperly handled secret grand jury materials connected to the case.

Boutros told Judge April Perry that he was unaware until recently of the alleged misconduct, AP reported. The allegations included claims that a prosecutor met with a grand juror outside of the proceedings and that other jurors who disagreed with dismissing the case prevented from participating.

Boutros did not dispute the allegations, the AP said. He told the judge the conduct was upsetting and explained that the dismissal reflected a decision to address the issues with the grand jury process. “No one acted with the intent to mislead your honor, and I think that they were following your order to give the law,” Boutros said in court, according to the AP report.

The case had been scheduled to go to trial the following week, making the Thursday dismissal the latest turn in a crackdown that triggered high-profile prosecutions in Chicago and surrounding suburbs. AP said the episode also reflected ongoing challenges for the Justice Department in pursuing cases involving allegations that people assaulted or hindered federal officers while protesting the Trump administration’s immigration crackdown.

The activist defendants included Kat Abughazaleh, an onetime Democratic congressional candidate, as well as Andre Martin, who was on Abughazaleh’s campaign staff; Oak Park village trustee Brian Straw; and Michael Rabbitt, a Democratic committeeperson, AP reported. Prosecutors had narrowed the case over time, after earlier charges were reduced.

In October, six people were initially charged with conspiring to impede an officer, a felony, according to the AP. Prosecutors alleged the group surrounded an immigration agent’s van with other protesters at a federal facility in the Chicago suburb of Broadview, which had been central to the Trump administration’s aggressive operation.

AP reported that charges were later dropped against two of the people. Last month, prosecutors scrapped the felony conspiracy charge altogether amid questions about the grand jury transcripts, and fresh charging documents did not spell out additional allegations.

During an earlier portion of the proceedings, Perry also limited public access, AP said, after Chicago Tribune, Chicago Sun-Times and other outlets objected. The judge closed part of the hearing to the public because it involved discussion of grand jury proceedings that are kept secret.

After the dismissal on Thursday, Perry issued a decision that the charges be dismissed with prejudice, meaning prosecutors could not refile them, AP reported. Perry also floated holding a separate hearing on possible sanctions for the U.S. Attorney’s Office.

Defense attorneys sought more information about the secrecy issue, AP reported. Abughazaleh’s defense attorney, Josh Herman, said the misconduct allegations that led to the dismissal were “sadly not surprising,” and that “This misguided case should have never been brought against Kat Abughazaleh or any of her co-defendants for exercising their protected First Amendment rights,” according to the AP report.

The AP report noted the case is not the first time during the Trump administration that prosecutors faced scrutiny over their conduct before grand juries, including a separate matter involving former FBI Director James Comey. In that earlier example, a federal judge in Virginia accused the Justice Department of what it described as a “disturbing pattern of profound investigative missteps” tied to the indictment process, and the case was later dismissed after a judge found a prosecutor who filed a prosecution was illegally appointed.