Without saying so explicitly, Sen. Jeff Flake (R-AZ) indicated Monday that the White House should allow the FBI to interview more than just the four people reportedly on its White House-approved list, in the bureau’s background investigation of sexual misconduct allegations against Supreme Court nominee Brett Kavanaugh.

“We certainly want the FBI to do a real investigation and we are working to make sure that that happens,” Flake said in an on-stage interview at the Forbes 30 Under 30 Summit in Boston, responding to a question about multiple reports that people who have tried to speak with the FBI in the course of that background investigation have been turned away. Trump on Monday blamed Senate Republicans for the limitations his White House Counsel’s Office has placed on the probe.

Flake initiated the probe by calling for it ahead of his vote approving of Kavanaugh’s confirmation in the Senate Judiciary Committee. Without him and other Republicans who supported the week-long investigation, Senate Majority Leader Mitch McConnell (R-KY) doesn’t have the votes needed to confirm Kavanaugh.

Flake continued on Monday: “I’ve had discussions, many yesterday, with my colleagues, with the White House Counsel’s Office, my staff is following up, as well. I had one of those conversations just five minutes ago, to make sure that any current, credible allegation that has been made is fully investigated.”

Flake said his office would be “having dialogue with the White House Council’s Office, making sure that it is up to standard.”

“It does no good to have an investigation that just gives us more cover, for example,” he continued. “We actually need to find out what we can find out. And we have to realize that we may not be able to find out everything that happened. This is something that was a while ago. Some witnesses or potential witnesses may not want to cooperate. But for those that can and those who we can compel to cooperate, we’ve got to do a fulsome investigation.”