A US federal judge says "investigative missteps" and "government misconduct" may have tainted the Trump administration's criminal case against former FBI director James Comey.
In a 24-page opinion, Judge William Fitzpatrick ordered justice department lawyers to release grand jury materials, including transcripts and evidence, to Comey's defence team.
Comey was charged in September after President Donald Trump called for his prosecution and appointed a new federal prosecutor to pursue the case.
Comey, who has long drawn Trump's ire, has pleaded not guilty to the charges, which include obstructing a congressional investigation.
The former FBI chief was fired by Trump during his first term, after Comey led an investigation into Russian election interference in the 2016 US presidential election. Since then, Comey has been a frequent target of the two-term US president.
