Representative Eric Swalwell, a California Democrat who has been a frequent critic of Donald Trump, filed a lawsuit on Tuesday claiming Federal Housing Finance Agency Director Bill Pulte abused his power to retaliate against one of the president’s political opponents.

Swalwell alleges Pulte obtained and used the lawmaker’s personal mortgage records in violation of US privacy laws and constitutional protections for political expression. Pulte sent a criminal referral to the US Justice Department earlier this month claiming Swalwell committed mortgage fraud, which the congressman’s lawyers said was false and “a gross mischaracterization of reality,” according to the court filing.

The federal lawsuit marks the latest escalation of accusations by prominent Democrats and other Trump critics that US officials are using the might and resources of the federal government to carry out a retribution campaign on behalf of the president.

Swalwell alleged that Pulte “abused his position” by searching the Fannie Mae and Freddie Mac databases to “concoct fanciful allegations of mortgage fraud” against prominent Democratic lawmakers. Pulte also made mortgage fraud referrals against New York Attorney General Letitia James and California Senator Adam Schiff, among others.