It’s been a busy 24 hours for Lev Parnas, an otherwise obscure Ukraine-born businessman who is suddenly at the center of President Donald Trump’s impeachment.

Parnas sat down for high-profile interviews Wednesday with MSNBC host Rachel Maddow and CNN host Anderson Cooper. During those interviews, which aired on Wednesday night and will continue Thursday, Parnas said the president knew about a Ukrainian scheme headed by Rudy Giuliani to obtain dirt on potential 2020 rival Joe Biden.

Here’s what we know about Parnas, highlights of what he told Maddow and Cooper, and how it might impact Trump’s upcoming Senate impeachment trial.

Who is Lev Parnas?

Parnas is a businessman who was born in Odessa, Ukraine, in 1972, when it was part of the Soviet Union. Parnas emigrated to the United States with his family when he was three years old and is a naturalized U.S. citizen. He reportedly played a key role aiding Rudy Giuliani, Trump’s personal attorney and the former mayor of New York City, in a scheme to pressure Ukraine to investigate former Vice President Joe Biden and his son, Hunter, who sat on the board of Burisma, a Ukrainian energy company.

Prior to his work with Giuliani, Parnas was a businessman in Florida, with the Miami Herald reporting he “left a long trail of debts in Florida and beyond.” He is now under indictment, and has pleaded not guilty to largely unrelated campaign finance charges alleging that he funneled money from foreign entities to U.S. political candidates. Parnas is also accused of hiding assets, including $1 million from a Russian oligarch with ties to the president’s former campaign chairman, Paul Manafort.

What was Parnas’ role in Ukraine?

Parnas and his partner, Igor Furman (who is also under indictment), reportedly helped set up meetings for Giuliani with Ukrainian officials in an attempt to discredit special counsel Robert Mueller’s report on 2016 election interference and to dig up dirt on Biden, the Democratic front-runner to challenge Trump’s re-election in 2020.

Claiming he worked under Giuliani’s direction, Parnas said his goal was to convince Ukraine to announce an investigation into Biden, and claimed part of the pressure campaign was threatening to cut off all aid to Ukraine — not just the security aid authorized by Congress.

Giuliani told the New York Times Wednesday that Parnas is “a proven liar,” but didn’t specifically dispute any of Parnas’ allegations.

What did Parnas tell Rachel Maddow and Anderson Cooper?

Though Parnas said he never spoke with Trump directly, he told Maddow he “wouldn’t do anything without the consent of Rudy Giuliani or the president.” He also said the only reason he gained access to political leaders in Ukraine was because he was working on behalf of Giuliani and Trump.

Parnas also claimed that Vice President Mike Pence was also involved in the scheme, telling Maddow a planned trip Kyiv for Ukrainian President Volodymyr Zelensky’s inauguration was canceled because of their refusal to publicly announce an investigation into Biden.

Marc Short, Pence’s chief of staff, didn’t deny Parnas’ allegations in a statement to the New York Times. Instead, Short said, Parnas “will say anything to anybody who will listen in hopes of staying out of prison.”

During his CNN interview, which will air in its entirety Thursday night, Parnas disputed Trump’s claim that his goal in Ukraine was to simply fight corruption, telling Cooper it was “all about 2020” and hurting a potential political rival in Biden.

How does Lev Parnas fit into Trump’s impeachment trial?

Parnas said he would be willing to testify in the upcoming Senate trial, and told Cooper he and former National Security Adviser John Bolton “could fill in all the dots.” Bolton has also said he would testify if subpoenaed, but it remains unclear if Senate Majority Leader Mitch McConnell will allow any witnesses to testify during the trial, which is expected to begin in earnest next week.

Parnas also provided a trove of documents, including text messages and letters, that were made public by the House Intelligence Committee on Tuesday. The documents appear to bolster his claims that he worked as part of Giuliani’s efforts in Ukraine.

Ukraine announced Thursday it had opened an investigation into the possible illegal surveillance of former U.S. ambassador Marie Yovanovitch, which was suggested in the documents Parnas provided to Congress.