By Diana Stancy Correll / Washington Examiner and Colorado Politics

The Senate Judiciary Committee is examining another allegation of misconduct against Supreme Court nominee Brett Kavanaugh, who has already been accused by three women of sexual misdeeds.

The allegation surfaced after U.S. Sen. Cory Gardner, R-Colorado, received an anonymous complaint claiming that Kavanaugh assaulted someone at a bar in 1998.

The sender said her daughter was present when the incident took place, along with several friends.

“When they left the bar (under the influence of alcohol), they were all shocked when Brett Kavanaugh, shoved her friend up against the wall very aggressively and sexually,” the letter says, per NBC News.

> RELATED: Colorado woman accuses Kavanaugh: Here’s all of CoPo’s coverage

NBC posted a copy of the letter here.

The letter claims there were at least four witnesses, including the sender’s daughter, who was living in Boulder at the time. No names were listed in the letter, which said that the victim doesn’t wish to reveal her identity.

Kavanaugh reportedly rejected the allegation when he was pressed about the incident by Republican Senate investigators from the Senate Judiciary Committee on Tuesday during a phone call.

Democrats, who were also privy to the phone call, did not believe Kavanaugh’s answers were sufficient and would like to probe the matter further, according to the report.

In a statement to Colorado Politics on Wednesday night, Gardner spokesman Casey Contres said:

On September 24th our Denver office received an anonymous letter in the mail about an alleged incident with Brett Kavanaugh in 1998. The letter contained no names, no address, and no contact info. Upon receiving the anonymous letter we immediately notified the Senate Judiciary Committee, which is handling the confirmation of Judge Kavanaugh. The letter was shared with both Republican staff and Democrat staff. Due to privacy regarding mail that comes into our office, we do not share the content of correspondence. Additionally, this anonymous letter contained no name or no contact info so our office is unable to contact the individual that sent the anonymous letter.

Kavanaugh faces several allegations of sexual misconduct, including one from a Colorado woman.

> RELATED: Gardner supports investigating Boulder woman’s new allegations against Kavanaugh

Christine Blasey Ford, who is expected to testify before the Senate Judiciary Committee on Thursday along with Kavanaugh, claims Kavanaugh forced himself onto her at a high school party in the 1980s.

Deborah Ramirez of Boulder also accuses Kavanaugh of exposing himself to her at a college party in the 1980s at Yale University when they were students.

Additionally, Julie Swetnick, who graduated from Gaithersburg High School in Maryland, claimed Wednesday she saw Kavanaugh and his friend Mark Judge drink “excessively” and “engage in highly inappropriate conduct” while attending house parties in the D.C. area in the early 1980s.

She claimed Kavanaugh and his friend Mark Judge tried to drug girls so they could “then be ‘gang raped'” by multiple boys. She also alleged that she was gang raped at a house party where Kavanaugh was present.

Kavanaugh has denied all allegations of sexual misconduct.