President Donald Trump’s lawsuit against the Internal Revenue Service over his leaked tax returns was filed for an “improper purpose,” a judge said Monday in a scathing decision that referred one of his lawyers for discipline and characterized the $10 billion complaint as an exercise in self-dealing.

U.S. District Judge Kathleen Williams accused Trump of having manipulated the court system when he sued a federal agency under his control, bypassing a requirement that parties in a lawsuit must have adverse interests and laying the groundwork for a settlement last spring that granted him immunity from tax audits and created a fund to compensate allies of the president who say they were unjustly persecuted.