The White House has warned that planned investigations of President Donald J. Trump’s administration may amount to “blatant criminality,” White House counsel Will Scharf wrote in a letter dated Monday.

“Threats to executive branch officials designed to deter them from public service, or process designed merely to abuse or instill fear in the recipient may cross the line into blatant criminality,” Scharf wrote. The letter’s existence was first reported by Punchbowl News and described in Associated Press accounts.

On Wednesday, Aaron Reitz, the U.S. attorney for the Southern District of Texas, directed that records be preserved in a Senate inquiry into donors to the White House ballroom project. Reitz wrote that the inquiry equated to threatening “citizens for associating themselves with the President and other public officials,” and said he was “taking the first step to stop this abuse of power.” He set a deadline of 6 p.m. Eastern on Nov. 18, and said failure to comply “may carry significant legal consequences.”

Acting Deputy Attorney General Trent McCotter wrote that “the First Amendment expressly prohibits Congress from infringing the speech and association rights of Americans” and that “DOJ will defend against threats to those rights, period.” Attorney General Todd Blanche said this week that Congress “has oversight authority. It always has, it always will,” and that the Justice Department “works with Congress to address questions they have.”