In an interview with CNN, Graham said he was intrigued by former Director of National Intelligence James Clapper's testimony
Monday when he declined to comment over whether he had any concerns with Trump business ties and Russia, saying it could influence an ongoing investigation.
"I want to know more about Trump's business dealings," Graham told CNN Tuesday. "I asked Clapper. 'I said, 'Is there any business dealings with the Trump organization that gave you concern?' And he said, 'No,' with a caveat, 'I don't know what the FBI is looking at so I don't want to run afoul with them.'"
Graham cautioned that his judiciary subcommittee might have to "steer clear" of the matter if it conflicts with the FBI probe into Russia and the Trump campaign, and he said he also wants to learn about whether the identities of Americans were unmasked and unlawfully leaked to the press for political purposes. But he also signaled he was interested in learning more about the business ties.
Asked if Trump's tax returns could be helpful to such an investigation, Graham said: "It could be, down the road."
Graham later clarified that his subcomittee was not actively looking into Trump's businesses, in response to a question from CNN on Senate Intelligence Chairman Richard Burr raising concerns about another panel looking into Trump's businesses.
"There's no effort by the judiciary committee to go after business interests because I don't know of any that are illegal or irresponsible, but if you can show me there is some evidence of that I'd be interested in it," Graham said.
Graham's comments come one day after his panel heard testimony from former acting Attorney General Sally Yates
, who detailed the steps she took to warn the White House that former national security adviser Michael Flynn was vulnerable to blackmail by the Russian government. The White House kept Flynn on staff for 18 days before he was ultimately dismissed by Trump, raising questions about why the then-national security adviser continued to hold such a high-profile position despite the concerns from Yates.
In the interview Tuesday, Graham said Trump was "very loyal" to Flynn and that the White House staff may have had to convince the President to dump him.
"Trump was very loyal to Flynn and (it) took a while for everyone to convince the President that Flynn had been compromised," Graham said. "I think the vice president was probably the strongest advocate to get rid of Flynn and the President eventually made the right decision."
Graham said earlier he wants to hear from former Obama national security adviser Susan Rice, who declined to appear at Monday's hearing
, to determine whether she was involved in the unmasking of any Americans.
"I don't know if we need to subpoena her," Graham said of Rice. "Here's what I want to know: Did any of this information about Michael Flynn cross her desk? Because somebody leaked it. I want to find out who that somebody was. One way you can do this is find out who had the information. How did Sally Yates become aware of the conversation between the Russian ambassador and Flynn? And who did she share that with. Did it go across the Susan Rice desk? I don't know."