An official inside the White House is prepared to testify he heard Donald Trump “appeal to Ukraine’s president to investigate one of his leading political rivals, a request the aide considered so damaging to American interests that he reported it to a superior,” according to the New York Times.

The Times reports a top Ukrainian expert on the National Security Council, Lt. Col. Alexander S. Vindman, twice made known his objections on how Ukraine was being treated by Trump and his inner circle.

Vindman will be the first White House official to testify who heard the call between Trump and the president of Ukraine. In his opening statement tomorrow, the Times reports, Vindman will say:

“I did not think it was proper to demand that a foreign government investigate a U.S. citizen, and I was worried about the implications for the U.S. government’s support of Ukraine. I realized that if Ukraine pursued an investigation into the Bidens and Burisma it would likely be interpreted as a partisan play which would undoubtedly result in Ukraine losing the bipartisan support it has thus far maintained.”

In addition, Vindman’s testimony appears to contradict some of Ambassador Gordon Sondland’s previous testimony to investigators.

Alexander Vindman is a decorated Iraq war veteran and he will also say he is not the whistleblower who first reported Trump’s pressure campaign on Ukraine.