A top U.S. State Department official is reportedly expected to tell House impeachment investigators on Saturday that he was unaware of an alleged push by Trump administration officials for Ukraine to announce an investigation into Joe Biden publicly.

The alleged push is at the center of the impeachment probe. A “whistleblower” complaint that Trump pressured Ukraine to investigate Biden and his son Hunter in exchange for aid triggered the ongoing impeachment probe.

Saturday’s testimony from Philip Reeker, the acting assistant secretary of state for European and Eurasian affairs, is expected to mark the third time that an impeachment inquiry witness suggests there was no effort to pressure Ukraine to investigate Biden.

Former U.S. Special Envoy to Ukraine Kurt Volker and American Ambassador to the European Union Gordon Sondland told investigators they were not involved in any effort to push for an investigation of Joe Biden and his son, Hunter. ‘

Volker and Sondland were heavily involved in America’s Ukraine policy.

House impeachment investigators subpoenaed Reeker after the State Department reportedly attempted to block his testimony behind closed doors in a rare Saturday session.

CNN revealed:

Acting Assistant Secretary of State Philip Reeker was expected to testify in the impeachment inquiry on Saturday that he did not find out there was a push by Trump administration officials for Ukraine to publicly announce investigations into Vice President Joe Biden and the 2016 election until the whistleblower complaint was made public, a source familiar with his testimony told CNN.

The “whistleblower” complaint became public on September 26.

To the dismay of Democrats, the CNN source indicated that Reeker will not confirm explosive allegations made by Acting Ambassador to Ukraine Bill Taylor during his deposition earlier this week.

In his opening remarks, Taylor testified that the Trump administration “conditioned” U.S. aid to Ukraine on the president of the Eastern European country announcing an investigation into Biden and his son.

Hunter Biden, the former vice president’s son, served on the board of directors of Burisman Holdings, a Ukrainian company linked to corruption.

Republican lawmakers said Taylor’s claim “collapsed” when he members of Congress questioned during his deposition.

Echoing Reeker, Volker told lawmakers there was no push for Ukraine to investigate Biden.

“At no time was I aware of or took part in an effort to urge Ukraine to investigate former Vice President Biden,” Volker said in his opening remarks.

Sondland added in his written testimony:

I recall no discussions with any State Department or White House official about Former Vice President Biden or his son, nor do I recall taking part in any effort to encourage an investigation into the Bidens.

… Withholding foreign aid in order to pressure a foreign government to take such steps [influence a U.S. election] would be wrong. I did not and would not ever participate in such undertakings.

Although House Democrats have conducted all the impeachment probe proceedings in private so far, the media have managed to obtain opening remarks of some of the witnesses.

Republicans have accused Democrats of leaking bits and pieces of information to fuel their impeachment agenda.

Democrats say they will eventually open the proceedings to the public, but will not say when.