Senate Judiciary Committee Chairman Chuck Grassley is redoubling his efforts to obtain documents related to Christine Blasey Ford’s accusation of sexual assault against Supreme Court nominee Brett Kavanaugh. In a Thursday evening letter to Ford’s legal team, Grassley again requested that they turn over the 2012 therapy notes that are the earliest corroborating evidence for Ford’s allegation, as well as materials from a polygraph test she took earlier this year—materials Ford’s attorneys have twice refused to hand over to the committee, although they maintain they would provide them to the FBI.

“You have claimed repeatedly that the evidence I have requested supports Dr. Ford’s allegatiosn against Judge Kavanaugh,” Grassley wrote. “Indeed, if the evidence supported your client’s allegations, you surely would produce it as quickly as you could. But you have repeatedly refused to produce this evidence to the Senate. In doing so, you are preventing the Senate from considering the evidence most crucial to Dr. Ford’s allegations.

“I don’t know what other inference we should draw from your refusal but that the withheld evidence does not support Dr. Ford’s allegations in quite the way you have claimed.”

Grassley further argued, as he has all along, that it is ultimately the responsibility of the Senate, not the FBI, to investigate the allegations against Brett Kavanaugh.

“If you have an objection to how the FBI conducts its investigations, take it up with Director Wray. But don’t raise that objection as a reason not to respond to this Committee’s demand for relevant evidence,” Grassley wrote. “The FBI’s investigative decisions aren’t our concern. Even if the FBI never interviews Dr. Ford, or interviews her ten times, this Committee has a constitutional obligation to investigate Dr. Ford’s allegations.”

Whether Ford’s legal team decides to honor Grassley’s latest request or not, the long-awaited Kavanaugh vote is at hand. A procedural vote to end debate on the nomination was scheduled for 10:30 a.m. Friday; if that motion passes, the Senate will proceed to a full confirmation vote as early as Sunday. Republicans have 48 “yes” votes locked down; out of four undecided senators—Susan Collins, Lisa Murkowski, Jeff Flake, and Joe Manchin—they need at least two to confirm the nominee. Republican leaders are confident they’ll get them, although Grassley said early Friday morning that, as of now, “I don’t really know” whether the votes are there. “And I don’t know whether anybody else does,” he said.

As they weigh how to vote, Senate Republicans are also reportedly considering a Thursday night Wall Street Journal report, which said that Leland Keyser, a friend of Ford’s who publicly stated that she knew nothing about Kavanaugh’s alleged assault, had been pressured by Ford’s allies, including a retired FBI agent, to revise her statement.