"What are these @WhiteHouse officials hiding from the American people?" tweeted Rep. Ted Lieu (D-CA).
"Also, this is yet more evidence of Obstruction of Congress, which is an impeachable offense," Lieu added.
The officials who did not come to Capitol Hill for questioning on Monday are:
+ John Eisenberg, the top lawyer on the National Security Council
+ Michael Ellis, the top deputy to Eisenberg
+ Robert Blair, a top adviser to acting Chief of Staff Mick Mulvaney
+ Brian McCormack, a senior official in the White House budget office.
The Tuesday witnesses who likely won't appear:
+ Wells Griffith, a White House energy expert
+ Michael Duffey, an official in the White House budget office.
Instead of getting testimony from White House officials, Democrats are ready to release another pair of transcripts from earlier closed door proceedings.
One transcript released on Monday from the former U.S. Ambassador to Ukraine, Marie Yovanovitch, showed that she was tipped off by Ukraine government officials to the work of President Trump's personal lawyer, Rudy Giuliani.
"I do not know Mr. Giuliani's motives in attacking me, Yovanovitch told investigators on October 11, as the former Ambassador said she first learned Giuliani was up to something in Ukraine in late 2018.
Yovanovitch said 'senior Ukrainian officials' were worried by Giuliani, telling her 'I really needed to watch my back,' the former ambassador added.
Asked about the testimony from his former Ambassador, President Trump offered little to reporters.
"I really don’t know her," Mr. Trump said, not mentioning that he said Yovanovitch was 'bad news' during his July 25 call with the leader of Ukraine.
Two more depositions are due out on Tuesday, from the acting U.S. Ambassador to Ukraine Bill Taylor, and the special U.S. envoy to Ukraine, Kurt Volker.