A US judge on Monday tossed out criminal charges against former FBI Director James Comey based on a procedural error, an extraordinary setback for the Justice Department in a case President Donald Trump called for as part of a campaign against perceived political enemies.

US District Judge Michael Nachmanoff in Alexandria, Virginia, determined the indictment brought against Comey in September was invalid because the grand jury that approved the charges had not seen the final version of the document.

The ruling is an embarrassing rebuke for Lindsey Halligan, a close Trump ally who took over the investigation as interim US attorney for the Eastern District of Virginia despite having no previous prosecutorial experience. Halligan, a former Trump personal lawyer, appeared alone before the grand jury after no career prosecutors agreed to sign on to the c