Lev Parnas told MSNBC's Rachel Maddow on Wednesday that he is "100 percent" certain Vice President Mike Pence canceled his trip to Ukrainian President Volodymyr Zelensky's inauguration last spring because Ukraine refused to announce it was investigating former Vice President Joe Biden and his son Hunter.Parnas, an associate of Rudy Giuliani, was indicted last year on campaign finance violations. Giuliani traveled extensively to Ukraine to try to find damaging information on Biden, a 2020 Democratic presidential candidate, and his son, who served on the board of the Ukrainian gas company Burisma.Parnas told Maddow that he was directed by Giuliani to deliver a "very harsh message" to Sergey Schafer, a senior Zelensky aide. He was told to make it clear that the U.S. would withhold all aid to Ukraine unless several demands were met. "A, the most important was the announcement of the Biden investigation," Parnas said. The day after Parnas met with Schafer, Pence canceled his scheduled trip to Ukraine.Parnas said he knows "100 percent" that the visit was called off in retaliation for Ukraine not going along with demands the country investigate the Bidens. "The chain of events, that was key to where we are today," he said. "After that, take a look at what transpires. Next within the next couple days, they realize that now they got word. Obviously when Pence cancels, they get word. So now they realize that what I was telling them was true." Pence "couldn't have not known" about the pressure campaign, Parnas alleges, as "everybody was in the loop."More stories from theweek.com The start of Trump's impeachment trial had solemn oaths, 'lengthy' yawns, 'pained expressions,' lots of lefties Sean Hannity, the biggest Trump insider at Fox News, says MSNBC and CNN are 'state-run TV' This Massachusetts 6-year-old is making clay koalas to raise funds for Australian animals