Schiff's panel and other committees will also try to conduct a series of depositions with certain key officials this week, while most lawmakers are out of town.
As for the President - while he was on Twitter over the weekend slamming Democrats over the impeachment effort - Mr. Trump made his case in a video released by the White House.
"What's going on now is the single greatest scam in the history of American politics," as the President tried to steer the conversation back to conventional political issues like the economy, guns, health care and more.
"We're fighting to drain the swamp," the President said, who lashed out specifically at House Intelligence Chairman Adam Schiff - and the still unnamed intelligence community whistleblower.
"I want Schiff questioned at the highest level for Fraud & Treason," Mr. Trump wrote on Twitter, labeling his accuser, "the so-called 'Whistleblower.'"
Democrats said the President's tweet seemed more like witness intimidation.
"Hard to imagine a more direct threat against this whistleblower," said Tommy Vietor, a former top aide to President Obama.
Meanwhile, the Sunday morning talk shows were filled with grist for the mill about the Ukraine situation, with top Trump aide Stephen Miller making the case that Ukraine should be investigating the Biden family - as Miller labeled the whistleblower case a 'partisan hit job.'
That type of answer ran into trouble on Fox News Sunday.
Along with Miller, the President's personal lawyer Rudy Giuliani has been making numerous TV appearances, attacking Democrats at every turn in recent days.
"Equal justice under law is at stake in this Witchunt," Giuliani tweeted, as Democrats mocked the former Mayor of New York.
"We had no choice but to move forward with an impeachment inquiry," said Schiff, who has taken more of a lead role in the impeachment effort by Democrats since the whistleblower story came out.
As for Speaker Pelosi, she made clear her reluctance to push for impeachment was totally changed by the details of the Trump phone call with the President of Ukraine.
If you have not read the whistleblower complaint - it can be found here.
The White House notes of the July 25, 2019 phone conversation involving the President and the Ukraine leader can be read here.