Alexander Vindman sues Donald Trump Jr., others for alleged witness intimidation over impeachment testimony

Vindman testified in the 2019 impeachment of then-President Donald Trump.

Former Lt. Col. Alexander Vindman has filed a lawsuit against Donald Trump Jr., Rudy Giuliani, former White House Deputy Chief of Staff Dan Scavino and former Trump White House official Julia Hahn, alleging they engaged in a conspiracy of witness intimidation against him over his testimony in then-President Donald Trump's 2019 impeachment.

Vindman, who was one of the few officials to directly listen into the July 2019 phone call between former President Trump and Ukrainian President Volodymyr Zelenskyy, outlines in the lawsuit what he describes as "an intentional, concerted campaign of unlawful intimidation and retaliation" over his role in Trump's impeachment.

"This campaign of intimidation and retaliation has had severe and deeply personal ramifications for Lt. Col. Vindman," Vindman's lawsuit says. "It also left a stain on our democracy."

Vindman is asking a federal judge to rule that Trump Jr., Giuliani, Scavino and Hahn all engaged in the conspiracy campaign, and to award him financial damages in an amount that would be determined after trial.

The lawsuit against the four alleges that they violated sections 1 and 2 of the Ku Klux Klan Act, which is intended to bar threats or intimidation against government officials carrying out their constitutional duties.

Neither Trump Jr., Giuliani, Scavino or Hahn immediately responded to ABC News' request for comment.

Vindman, in the suit, also ties the alleged harassment campaign against him to the ongoing investigation by the House select committee on the Jan. 6 attack on the U.S. Capitol.

The suit claims that the message sent to Vindman "reverberates to this day, as witnesses subpoenaed by Congress in connection with its investigation into the events of January 6, 2021, continue to heed former President Trump's instructions to defy those subpoenas, undermining Congress's constitutional oversight role and the fundamental principle of checks and balances between three co-equal branches of government."