President Trump released a transcript of an April call with Ukrainian President Volodymyr Zelensky on Friday, as House investigators prepared to hear public testimony Marie Yovanovitch, a former ambassador to Ukraine who was recalled earlier this year.

Yovanovitch has previously testified that she was the target of a shadow campaign to orchestrate her removal that involved Trump’s personal attorney Rudolph W. Giuliani.

Friday afternoon, David Holmes, a staff member of the U.S. Embassy in Ukraine, is scheduled to appear for a closed-door deposition. He is said to have overheard a call in which Trump sought information about investigations that could benefit him politically.

Democrats are seeking to build a case that Trump sought to withhold military assistance and an Oval Office meeting until Zelensky announced investigations into former vice president Joe Biden and his son, as well as an unfounded theory that Ukrainians interfered in the 2016 presidential election to hurt Trump.

●How the impeachment inquiry has revealed a long and murky campaign to oust a veteran U.S. ambassador.

●For Trump, Yovanovitch’s testimony brings moment of reckoning on gender.

●Career White House budget official expected to break ranks, testify in impeachment inquiry.