WASHINGTON — Lawyers for two women who accuse Supreme Court nominee Brett Kavanaugh of sexual misconduct say they fear the FBI is not conducting a thorough investigation, as Republican leaders steer toward a decisive vote on the nomination this week.

Attorneys for Christine Blasey Ford, who says she was sexually assaulted by Kavanaugh at a party when they were teenagers, wrote a letter to FBI Director Christopher Wray asking why the FBI hasn't contacted their client after she offered to cooperate in the FBI's reopened background investigation of Kavanaugh.

Also Tuesday, an attorney for another accuser, Deborah Ramirez, said he's seen no indication that the FBI has reached out to any of the 20 people who Ramirez told them may be able to corroborate her account that Kavanaugh exposed himself to her when they were Yale freshmen. The attorney, John Clune, said Ramirez was interviewed by the FBI on Sunday and provided agents with the witnesses' contact numbers.

Clune said he is concerned that the bureau “is not conducting — or not being permitted to conduct — a serious investigation.”

Demonstrating that the investigation is credible is crucial as the White House and Senate Republican leadership look to win the support of several wavering senators — including three Republicans — who will determine whether the 53-year-old conservative judge is confirmed to the lifetime post.

One Republican official said he'd been told it was possible the FBI investigation could be completed as soon as Tuesday night or Wednesday morning, but it remained unclear. The official revealed the private conversations only on condition of anonymity.

Senate Majority Leader Mitch McConnell said, “I can tell you with certainty” that the FBI report will be finished and the Senate will vote this week, though he didn't specify when. Because of procedural steps, a final confirmation vote was unlikely until late in the week, perhaps over the weekend.

When Trump ordered the FBI investigation last week under pressure from a handful of Senate Republicans, he set a deadline of this Friday for the probe's completion.

Details were scant about precisely who the FBI was interviewing and the scope of the probe, but agents are known to have interviewed at least four people.

They include Mark Judge, who Ford has said was in the bedroom where, she says, a drunken Kavanaugh sexually attacked her at a 1982 high school gathering. Also interviewed were two other people Ford said were present but in a different room: Patrick “P.J.” Smyth and Leland Keyser. Judge, Smyth and Keyser say they don't recall the incident.

Kavanaugh has denied the accusations by Ford and Ramirez and those by a third woman, Julie Swetnick, who has alleged she was victimized at a party attended by Kavanaugh.