All charges against four activists who protested outside a federal building during last year’s immigration crackdown in Chicago have been dropped in an unusual hearing where a top federal prosecutor appeared to acknowledge grand jury misconduct by his office. U.S. Attorney Andrew Boutros announced the decision to dismiss remaining charges following a closed-door hearing over redacted grand jury transcripts. In open court, he told U.S. District Judge April Perry he was unaware and upset by the misconduct allegations, including a prosecutor meeting with a grand juror outside proceedings.