President Trump’s effort to avoid impeachment took another serious hit on Wednesday.

“Trump has denied wrongdoing. But evidence against him is mounting as more witnesses trudge to Capitol Hill to testify, and as investigators release their testimonies in full,” reports Politico

The latest evidence came in a transcript of last month’s closed-door testimony from the top U.S. diplomat in Ukraine released by the House Intelligence Committee, which leads the impeachment inquiry.

That testimony from acting ambassador William Taylor explicitly contradicts the president’s oft-repeated claim that there was “no quid pro quo” involved when he asked Ukraine’s president to investigate one of his chief political rivals, former vice president Joe Biden.

According to the transcript, Rep. Adam Schiff (D-CA), the intelligence committee chairman, asked what Taylor meant when he said nearly $400 million in military aid to Ukraine, as well as a meeting between Trump and the Ukrainian president, were “conditioned” by the White House on Ukraine launching such an investigation.

Shiff asked: “…when you talk about conditioned, did you mean that if they didn’t do this, the investigations, they weren’t going to get that, the meeting and the military assistance?”

Taylor responded: “That was my clear understanding, security assistance money would not come until the President committed to pursue the investigation.”

Schiff: So if they don’t do this, they are not going to get that, was your understanding?

Taylor: Yes, sir. 

Schiff: Are you aware that quid pro quo literally means this for that

Taylor: I am.

Taylor’s testimony pointed to Trump’s personal lawyer, Rudy Giuliani, as Trump’s apparent point man in the effort to force Ukraine’s government to investigate Biden and a Ukrainian company that employed Biden’s son, Hunter. Taylor called that an “irregular channel” for diplomacy. Giuliani is not employed by the U.S. government.

This week, Gordon Sondland, U.S. ambassador to the European Union, backed Taylor’s account in a revision of his own testimony to the impeachment inquiry, 

In that revised testimony, reports the Washington Post, Sondland “corroborated Taylor’s account that Ukraine was told U.S. military assistance would resume only if investigations that could be damaging to former vice president Joe Biden commenced.”

Taylor is scheduled to be among the first witnesses next week, when the impeachment inquiry begins public testimony.