Week three of the House Democrats' impeachment inquiry into President Donald Trump has wrapped - and so much happened.

It included a number of dramatic moments, from efforts by the White House to block progress in the investigation, to a marathon testimony from the former ambassador to the Ukraine and, of course, some choice words.

Central to the impeachment probe is whether Trump used the threat of withholding military aid to pressure Ukraine's leader to conduct an investigation into Trump's 2020 rival Joe Biden. That's the allegation that came out of an anonymous whistleblower complaint, which Trump accused of being partisan this week.

While Congress was still technically on recess this week, key developments took place. Here's what happened:

Giuliani associates, witnesses in probe, arrested

On Wednesday evening, two Ukrainian-born businessmen and associates of Trump's lawyer Rudy Giuliani were arrested on campaign finance charges.

Igor Fruman and Lev Parnas helped Giuliani meet with a Ukrainian prosecutor as part of Giuliani's involvement with the push for Ukraine to investigate Biden. They were both scheduled to appear before Congress this week, but were arrested shortly before their slotted appearances. The two were then subpoenaed by House Democrats to testify.

Federal authorities said the businessmen's campaign contributions “conspired to circumvent the federal laws against foreign influence by engaging in a scheme to funnel foreign money to candidates for federal and state office so that the defendants could buy potential influence with candidates, campaigns and the candidates’ governments."

The two were mega donors to Republican campaigns.

On Friday, The New York Times reported Giuliani is under investigation by federal prosecutors for his dealings in Ukraine.

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White House ramps up opposition to the inquiry

The administration is refusing to comply with requests for documents and witnesses related to the Ukraine scandal, the White House said on Tuesday, calling it a "partisan inquiry."

Speaker of the House Nancy Pelosi, D-Calif., said in response that the White House's actions may be considered evidence of obstruction.

A key figure in the Ukraine controversy, Ambassador to the European Union Gordon Sondland, was scheduled to appear before Congress on Tuesday, but the State Department blocked him from testifying at the last minute. So, House Democrats subpoenaed him.

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Sondland says he'll testify anyway

Sondland said Friday he will testify Thursday instead, an effort to comply with the House subpoena.

Democrats are interested in text messages he is believed to have on his personal phone, some of which were revealed after Kurt Volker's closed-door testimony last week.

"Are we now saying that security assistance and WH meeting are conditioned on investigations?" Top Ukraine diplomat Bill Taylor asked in a text message to Volker and Sondland on Sept. 1.

"Call me," Sondland texted back.

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Ousted Ukraine ambassador appears before Congress

Former Ambassador to Ukraine, Marie Yovanovitch, testified on Friday in a 10-hour session before Congress that Trump "pressured" the State Department to remove her from her post in a "concerted campaign" against her.

Yovanovitch appeared despite a State Department direction not to testify.

"We need to rebuild diplomacy as the first resort to advance America’s interests and the front line of America’s defense," she said in her opening statement. "I fear that not doing so will harm our nation’s interest, perhaps irreparably."

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Trump and Biden escalate rhetoric

In campaign stops this week, Trump dished out new rally material targeting the Bidens and top Democrats involved in the impeachment probe.

"They want to erase your vote like it never existed. They want to erase your voice and they want to erase your future. But they will fail because in America the people rule again," Trump said in Minnesota on Thursday.

And Biden has for the first time stated strongly that he is in favor of Trump's impeachment. In the past, his comments on impeachmient have been conditional on failure to cooperate with the inquiry.

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What's next on the impeachment agenda?

Next week, Congress officially returns from its two-week recess, and has a slew of depositions and subpoena deadlines on the agenda.

Another Giuliani associate, Semyon Kislin, is scheduled to be deposed on Monday. Also on Monday is the deadline for Sondland to produce documents in response to the subpoena. Fiona Hill, a former Trump adviser on Russia, is also scheduled for a deposition Monday.

Giuliani and Vice President Mike Pence have deadlines to produce documents coming up next week, but both have indicated they will not comply.

Other news this week: