A federal judge referred Philadelphia District Attorney Larry Krasner to federal prosecutors Tuesday, finding that he and a senior assistant may have broken the law while trying to conceal how their office supported overturning a murder conviction.

U.S. District Judge Paul Diamond disqualified Krasner and Assistant District Attorney Matthew Stiegler from participating in the case, concluding that their personal interests conflicted with their responsibilities as prosecutors. Krasner, an elected Democrat, has been roiled by critics including President Donald Trump and Republicans in the state who’ve accused his office of implementing soft-on-crime policies under his direction.