Two University of St. Thomas law professors who signed separate letters in support of Judge Brett Kavanaugh's nomination to the U.S. Supreme Court are now calling for an FBI investigation into allegations of sexual misconduct against him.

A third says he continues to support the nomination ahead of a Thursday hearing with one of Kavanaugh's accusers and believes lawmakers in the U.S. Senate should decide what comes next.

One of the faculty members calling for an investigation, Mark Osler, knew Kavanaugh well in the late 1980s when they both attended Yale Law School. He says he never witnessed behavior similar to that described by three women accusing Kavanaugh of misconduct in high school and college. But Osler, a former federal prosecutor who signed an August letter to lawmakers with 22 other classmates of Kavanaugh's, says these allegations merit a thorough investigation before a confirmation vote. Another St. Thomas faculty member, Greg Sisk, who joined 150 legal scholars in backing the nomination, also says the FBI must step in.

"Judge Kavanaugh is one of the most exemplary judges of our era; he is an excellent judge whether you agree with his positions or not," Sisk said. But, he added, "These are serious allegations that deserve to be taken seriously."

Lyman Johnson, a St. Thomas corporate law professor who signed the letter with Sisk, says he stands by that signature.

"I still support him and, like others of goodwill, I await Thursday's hearings to see if anything changes my mind," he said.

Osler graduated with Kavanaugh from Yale Law School, where he says they were part of the same social circle and worked together on the university's law journal.

A Democrat, Osler says he disagrees with Kavanaugh on numerous issues. But after reading Kavanaugh's legal opinions and speaking with attorneys who have argued cases in front of him, he chose to back his nomination.

But Osler and Sisk, who describes himself as a lifelong Republican, both said they came to question their support after Christine Blasey Ford accused Kavanaugh of assault when they were both teenagers. Two more women have since alleged incidents of sexual misconduct involving Kavanaugh.

Osler and Sisk said the Senate should pause the confirmation hearings while the FBI investigates.

Johnson said he felt it was important to back Kavanaugh's nomination to show he enjoys support within the legal academia, where Johnson says he is in a small minority of conservative professors. Johnson says he still supports the nomination and expects the Judiciary Committee to continue to drive the confirmation process.