Former Vice President Joe Biden lashed out at Senate Judiciary Chairman Lindsey Graham (R-SC) for launching an investigation into whether Biden abused his office when he had Ukraine's top prosecutor fired while he was looking into Burisma Holdings, the Ukrainian gas company paying Hunter Biden to sit on its board.

"Lindsey is about to go down in a way that I think he’s going to regret his whole life," Biden told CNN host Don Lemon in a Friday interview in South Carolina.

"I say Lindsey, I just — I’m just embarrassed by what you’re doing, for you. I mean, my Lord."

"They have him under their thumb right now. They know he knows that if he comes out against Trump, he’s got a real tough road for reelection, number one," Biden continued. "He knows me; he knows my son; he knows there’s nothing to this. Trump is now essentially holding power over him that even the Ukrainians wouldn’t yield to. The Ukrainians would not yield to, quote, ‘investigate Biden’ — there’s nothing to investigate about Biden or his son."

Biden tells @donlemon he's "embarrassed by" Graham's actions after senator asks Pompeo to turn over docs related to Hunter and Ukraine



"Lindsey is about to go down in a way that I think he’s going to regret his whole life," Biden says, adding Trump is "holding power" over him pic.twitter.com/sjNjQV7Ogp — Manu Raju (@mkraju) November 22, 2019

On Thursday, Graham sent a letter to Secretary of State Mike Pompeo seeking all documents and communications related to Joe Biden's phone calls with Ukraine's former president Petro Poroshenho which occurred Feb. 11, 18 and 19 as well as March 22, 2016, citing media reports that the two discussed firing the Prosecutor General, Viktor Shokin.

In addition, Graham is seeking all documents and communications between Biden, his office, and Poroshenko's office spanning the period from when Burisma founder Mykola Zlocheveky's home was raided and Shokin was dismissed.

Graham notes in his letter that Hunter Biden followed longtime Joe Biden aide Tony Blinken over Twitter, the day that Interfax reported that Zlochevsky's property had been seized - suggesting the two may have discussed Shokin's investigations, per Politico.

In response to Biden's comments on Graham, Trump attorney Rudy Giuliani suggested the former Vice President was threatening the Senator, and was "getting to be more and more like my old mafia cases," adding "They sure do sound like crooks."