Senator Ron Johnson (R., Wi.), chairman of the Senate Homeland Security Committee, is working on verifying a document which details a “misinformation campaign” against Ukrainian prosecutor Victor Shokin, who Joe Biden bragged about getting fired.Johnson told Fox News Wednesday that the document, still needs to be verified, “raises some eyebrows” regarding the rationale behind Shokin’s dismissal from his post as Ukrainian prosecutor general in 2016.“I know it was a big explanation that everybody wanted him fired, but there is a document, we have to verify it, but there is a document supposedly contemporaneous that said that the contact by Blue Star to the prosecutor general’s office was all about apologizing for the misinformation campaign conducted against Shokin,” Johnson said.President Trump and Republican allies have repeatedly harped on the fact that Joe Biden, who was point man for the White House in Ukraine at the time, threatened to withdraw $1 billion in U.S. aid to Ukraine if the country did not fire Shokin, who was accused by the State Department and U.S. allies in Europe of being soft on corruption.Johnson, who first asked in November for documents relating to Hunter Biden’s role at Burisma and his interactions with State Department officials, wants to subpoena former Ukrainian embassy official Andrii Telizhenko, who worked as a consultant for the Washington-based Blue Star Strategies.Documents released in November show how Blue Star Strategies, which was hired by Burisma to help deal with corruption allegations, tried to leverage the Biden name to secure a meeting with the State Department as part of a campaign to rehabilitate Burisma’s image.Johnson brought up Blue Star’s use of Hunter Biden on Wednesday, and said that his probe aims to let “the American people see what this possible corruption is.”President Trump, asked by Sean Hannity about Johnson’s probe later Wednesday, said the Bidens and Burisma “will be a major issue in the campaign” if Joe Biden becomes the Democratic nominee.“I will bring that up all the time because I don’t see any way out for them. I don’t see how they can answer those questions. I hope they can, I’d actually prefer it that they can’t but I don’t believe they will be able to answer those questions. That was purely corrupt,” Trump said.