Democrat Sen. Joe Donnelly called Wednesday for the FBI to investigate the allegations against Supreme Court nominee Brett Kavanaugh, after a third woman came forward with accusations against the judge.

“The allegations raised against Judge Kavanaugh are serious, merit further review, and I believe should be investigated by the FBI," Donnelly said in a statement. "I will continue to get as much information as I can, including by following Thursday’s scheduled hearing.”

Julie Swetnick said she witnessed efforts by Kavanaugh and a classmate to get girls inebriated at parties in high school so they could be "gang raped," according to a signed statement her attorney Michael Avenatti released Wednesday.

She also said the two were present when she was gang raped, but did not say Kavanaugh sexually assaulted her.

Two other women, Christine Blasey Ford and Deborah Ramirez, previously came forward with sexual assault allegations against Kavanaugh.

Kavanaugh has vehemently denied all of the allegations. He called Swetnick's accusations "ridiculous and from the Twilight Zone."

"I don’t know who this is and this never happened," Kavanaugh added.

More:Here are all of the allegations against Judge Brett Kavanaugh and how he has responded

More:Mike Braun supports second hearing for Kavanaugh but defends judge's 'sterling record'

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Donnelly has so far refrained from indicating how he will vote if Kavanaugh reaches a full Senate vote. The Senate Judiciary Committee is scheduled to vote on Kavanaugh's nomination on Friday, the day after Ford is set to testify.

Before the accusers came forward, Donnelly was facing pressure from both sides of the aisle on how to vote on Kavanaugh.

The political calculus at that time was that if Donnelly voted against Kavanaugh he risked alienating Republicans that he needed to earn favor with in order to beat his GOP opponent Mike Braun in the November election. And if he voted for Kavanaugh, he risked angering his base.

The recent allegations throw those dynamics into unpredictable disarray, some political observers say.

After Ford came forward saying Kavanaugh sexually assaulted her when they were teenagers, Donnelly called for the vote on Kavanaugh to be postponed.

Later that week, Braun issued a statement saying he supported a second hearing for Kavanaugh, but still praised the judge.

“I support Senator Grassley’s decision to have these 11th hour allegations thoroughly reviewed by the Senate Judiciary Committee, and weighed against Judge Kavanaugh’s decades of public service, sterling record on the bench, outstanding personal reputation, and his unequivocal denial of the allegations," Braun said at the time.

In interviews with Hugh Hewitt earlier this week, Braun said the process looks orchestrated, "the evidence is weak," and "it looks like typical Chuck Schumer tactics" because of the timing of the revelations.

Braun's campaign did not return emails requesting comment on the most recent allegation.

Call IndyStar reporter Kaitlin Lange at 317-432-9270. Follow her on Twitter: @kaitlin_lange.