Lindsey Graham laid out three areas he wants to explore as part of his "deep dive" inquiry into the origins of the Trump-Russia investigation after the conclusion of Justice Department Inspector General Michael Horowitz’s investigation into alleged abuse of the Foreign Intelligence Surveillance Act.

During an interview Wednesday evening, Fox News host Sean Hannity asked the South Carolina Republican senator where he plans to go with his investigation. Graham, the chairman of the Judiciary Committee, said there are questions he wants to ask former FBI Director James Comey and his deputy Andrew McCabe.

"I'd want to ask Comey, what did you tell the president in January of 2017, 'Here is the dossier, I can’t verify it, but I want you know about it,'" Graham said. "And he used the same document and told the court that it was reliable on four different occasions. I want to know when McCabe reaffirmed again that without the dossier that there would be no warrant."

He was referring to Foreign Intelligence Surveillance Act warrants filed by the FBI to surveil onetime Trump campaign adviser Carter Page. Four FISA warrant applications and renewals were filed from October 2016 through June 2017 against Page. Robert Mueller was appointed special counsel of the Russia investigation in May 2017, after President Trump fired Comey.

The applications relied heavily on the unverified dossier about Trump's ties to Russia compiled by British ex-spy Christopher Steele, who was hired by Fusion GPS. The opposition research firm was hired by Marc Elias of the Perkins Coie law firm at the behest of the Hillary Clinton presidential campaign. Steele and Fusion GPS shopped the research around to various government figures, including one skeptical State Department official, as well as the media in the run-up to the 2016 election.

McCabe has accused Republicans of mischaracterizing his testimony about the dossier.

Graham said he also wants to know what exactly former Trump campaign adviser George Papadopolous told the FBI.

"I want to find out, did Papadopoulos tell them upfront that, you know, if I was working with the Russians that would be a crime. I would never do that," Graham said. "I want to know a bunch of things things."

Papadopolous pleaded guilty October 2017 to making false statements to the FBI about his contacts with Russians and served 12 days in federal prison late last year and is now on supervised release.