Sen. Lindsey O. Graham (R-S.C.) said Sunday that the Justice Department is vetting information that President Trump’s personal attorney has delivered regarding Hunter Biden’s work on the board of a Ukrainian energy company.

Graham, citing an early-morning conversation with Attorney General William P. Barr, said that Rudolph W. Giuliani is giving his information to national security experts and that he would back off his own plans to use the Senate Judiciary Committee as a vehicle to investigate the Biden family.

“The Department of Justice is receiving information coming out of the Ukraine from Rudy to see — he told me that they have created a process that Rudy could give information and they would see if it’s verified,” Graham, the chairman of the Judiciary Committee, said on CBS’s “Face the Nation.”

He warned that Giuliani might be getting bad information from his trips to Ukraine as part of a disinformation campaign by Russian security experts, citing their effort to disrupt the 2016 presidential campaign.

The Department of Justice declined to comment.

“If Rudy Giuliani has any information coming out of the Ukraine, he needs to turn it over to the Department of Justice, because it could be Russian propaganda,” Graham said.

Giuliani’s fraught relationship with the Justice Department has been the subject of intense public and private debate. For months, federal prosecutors in New York have been investigating Giuliani’s business ties to two men indicted on campaign finance charges, according to people familiar with the matter.

Last year, Giuliani and other lawyers advocating on behalf of a Venezuelan businessman met privately with the head of the department’s criminal division. Since then, Justice Department officials have tried to put greater distance between themselves and the president’s personal lawyer.

Barr has counseled Trump in general terms that Giuliani has become a liability and a problem for the administration, according to people familiar with the conversations.

In one of those conversations, the attorney general warned the president that he was not being well-served by his lawyer, one person with knowledge of the episode said.

Graham said he called Barr and Sen. Richard Burr (R-N.C.), chairman of the Senate Intelligence Committee, on Sunday morning after hearing about Giuliani’s interview Saturday night on Fox News’s “Watters’ World.” During the interview, the former New York City mayor made various claims about the information he has cobbled together from Ukrainian sources and said Graham should use his committee to investigate the Bidens.

“Lindsey, get started. Yes, I have — I have what I used to call when I was U.S. attorney, a smoking gun,” Giuliani said.

Then, just as “Face the Nation” started Sunday morning, Trump sent out a tweet urging Graham to launch an undefined investigations. “He must start up Judiciary and not stop until the job is done. Clean up D.C. now, last chance,” Trump said in the tweet, which CBS’s Margaret Brennan read to the senator on air.

Graham appeared to back away from his assertions in recent weeks that he would lead a probe into former vice president Joe Biden’s time overseeing Ukraine policy while his son served on the board of Burisma, a Ukrainian energy company.

“I’m not going to be the Republican Christopher Steele,” Graham said, mentioning the former British spy whose investigations for Republican and Democratic rivals of Trump in 2016 were eventually sent to the Justice Department.

He said that after talking to Barr and Burr, he worried Giuliani’s information might not be trustworthy. “Take very cautiously anything coming out of the Ukraine, against anybody,” Graham said.

The South Carolina Republican has been a central player in Trump’s orbit for months, as the president’s close allies have sought to pressure the senator to use his committee as an investigative cudgel against rivals.

His position Sunday returned Graham to where he was in the early fall, saying that he would focus his committee work on the FBI’s handling of the 2016 investigation and how surveillance warrants were obtained.

By late November, however, Graham had sent a letter to the State Department requesting documents related to Biden’s 2016 calls to the then-president of Ukraine, Petro Poroshenko, who lost his reelection bid last year to Volodymyr Zelensky.

Trump’s legal team mounted a defense in the Senate impeachment trial that suggested the president was warranted in asking Zelensky to investigate Burisma for corruption — an apparent effort to rebut testimony from administration officials that his motive was to hurt Biden’s 2020 presidential campaign.

Biden’s work to pressure Ukraine to fire a top prosecutor had bipartisan support in Congress, where many maintained that a shake-up in that office would lead to more aggressive anti-corruption investigations.