Nearly three years after Justice Brett M. Kavanaugh’s tumultuous confirmation to the Supreme Court, the F.B.I. has disclosed more details about its efforts to review the justice’s background, leading a group of Senate Democrats to question the thoroughness of the vetting and conclude that it was shaped largely by the Trump White House.
In a letter dated June 30 to two Democratic senators, Sheldon Whitehouse of Rhode Island and Chris Coons of Delaware, an F.B.I. assistant director, Jill C. Tyson, said that the most “relevant” of the 4,500 tips the agency received during an investigation into Mr. Kavanaugh’s past were referred to White House lawyers in the Trump administration, whose handling of them remains unclear.
The letter left uncertain whether the F.B.I. itself followed up on the most compelling leads. The agency was conducting a background check rather than a criminal investigation, meaning that “the authorities, policies, and procedures used to investigate criminal matters did not apply,” the letter said.