Sen. Dianne Feinstein, the ranking Democrat on the Senate Judiciary Committee, sent a letter to the White House counsel and the FBI director on Sunday asking for a copy of the directive issued to the FBI that lays out the scope of the investigation into Supreme Court nominee Brett Kavanaugh.

“Given the seriousness of the allegations before the Senate, I am writing to request that you provide the Senate Judiciary Committee with a copy of the written directive sent by the White House to the FBI,” the California Democrat’s letter to counsel Don McGahn and Director Christopher Wray says.

“In addition, if the FBI requests any expansion beyond the initial directive, please provide the names of any additional witnesses or evidence,” the letter continued.

Sen. Chuck Grassley, the chairman of the committee, approved the investigation Friday and the White House ordered the FBI to conduct a supplemental probe into the allegations of sexual misconduct against Kavanaugh.

But news reports have said the White House is trying to narrow the scope of the investigation and limit the number of people who can be interviewed.

In emotional testimony Thursday, Christine Blasey Ford accused Kavanaugh of holding her down on a bed, groping her and stopping her from calling out during a high school party in 1982.

GOP Sen. Jeff Flake of Arizona asked Grassley to delay a final confirmation vote on Kavanaugh in the Senate for a week until the FBI examines Ford’s claims.