Friend of Dr. Ford Felt Pressure to Revisit Statement At issue is statement to committee that she knew nothing about alleged sexual assault by Brett Kavanaugh.

The statement to the FBI offers a glimpse into how Dr. Ford’s allies were working behind the scenes to lobby old classmates to bolster their versions of the alleged incident, as were Judge Kavanaugh’s.

Judge Kavanaugh, whose Supreme Court nomination will be debated in the Senate Friday, has denied the allegations of sexual misconduct.

On Thursday, a day after sending to the White House the report on its investigation into the allegations against Judge Kavanaugh, the FBI sent the White House and Senate an additional package of information that included text messages from Ms. McLean to Ms. Keyser, according to a person familiar with the matter.

Ms. McLean’s lawyer, David Laufman, said in a statement: “Any notion or claim that Ms. McLean pressured Leland Keyser to alter Ms. Keyser’s account of what she recalled concerning the alleged incident between Dr. Ford and Brett Kavanaugh is absolutely false.”

Ms. Keyser’s lawyer on Sept. 23 said in a letter to the Senate Judiciary Committee that she had no recollection of attending a party with Judge Kavanaugh, whom she said she didn’t know. That same day, however, she told the Washington Post that she believed Dr. Ford. On Sept. 29, two days after Dr. Ford and the judge testified before the Senate Judiciary Committee, Ms. Keyser’s attorney sent a letter to the panel saying his client wasn’t refuting Dr. Ford’s account and that she believed it but couldn’t corroborate it.

A person close to the former classmates said it was her understanding that mutual friends of Dr. Ford and Ms. Keyser, including Ms. McLean, had contacted Ms. Keyser after her initial statement to warn her that her statement was being used by Republicans to rebut the allegation against Judge Kavanaugh. The friends told Ms. Keyser that if she had intended to say she didn’t remember the party—not that it had never happened—that she should clarify her statement, the person said, adding that the friends hadn’t “pressured” Ms. Keyser.

Judge Kavanaugh and his allies also lobbied former classmates to defend him. Ahead of a Sept. 23 New Yorker article about an allegation by Deborah Ramirez that Judge Kavanaugh had exposed himself to her in their freshman year at Yale, a former classmate, Karen Yarasavage, said she had gotten a call from “Brett’s guy” and that “Brett asked me to go on record,” according to a memo about the conversation by another former classmate. Ms. Yarasavage is quoted anonymously in the New Yorker piece, the memo said. The judge denied the claim that he exposed himself.

Judge Kavanaugh, in a Wall Street Journal op-ed Thursday, said he had been “subjected to wrongful and sometimes vicious allegations” and that his youth had been “ridiculously distorted.”

If confirmed, he wrote, he would “keep an open mind in every case, and always strive to preserve the Constitution.”

Ms. Keyser’s interview with the FBI—which is subject to perjury laws—may influence the Senate debate on the judge’s confirmation. Sen. Bob Corker (R., Tenn.), who has said he would vote to confirm Judge Kavanaugh, told reporters earlier Thursday that he found the most significant interviews in the FBI report to be those from people close to Dr. Ford who wanted to corroborate her account and were “sympathetic in wishing they could, but they could not.”

Howard Walsh, a lawyer for Ms. Keyser, declined to comment.

The FBI declined to comment on the investigation.

There is no indication Dr. Ford and her legal team were involved in any effort to discuss Ms. Keyser’s statement with her, according to people familiar with the matter. The FBI didn’t interview Dr. Ford for its investigation, which her lawyers late Wednesday said wasn’t appropriately comprehensive and “cannot be called an investigation.”

Attorneys for Dr. Ford declined to comment for this article.

In his testimony last week, Judge Kavanaugh sought to use Ms. Keyser’s initial statement to undercut his accuser. “Dr. Ford’s allegation is not merely uncorroborated, it is refuted by the very people she says were there, including by a long-time friend of hers,” he said. “Refuted.”

Two days later, Ms. Keyser’s lawyer said in a letter to the Senate Judiciary Committee: “Ms. Keyser does not refute Dr. Ford’s account, and she has already told the press that she believes Dr. Ford’s account.” Mr. Walsh added: “However, the simple and unchangeable truth is that she is unable to corroborate it because she has no recollection of the incident in question.”

In her testimony before the Senate Judiciary Committee last week, Dr. Ford said she had never told Ms. Keyser about her assault. “She didn’t know about the event. She was downstairs during the event and I did not share it with her,” Dr. Ford said.

Dr. Ford also said she didn’t “expect” that Ms. Keyser would remember the evening, calling it a “very unremarkable party.” She added: “Leland has significant health challenges, and I’m happy that she’s focusing on herself and getting the health treatment that she needs, and she let me know that she needed her lawyer to take care of this for her, and she texted me right afterward with an apology and good wishes, and et cetera.”

This is Ms. McLean’s second appearance in the weekslong drama around Judge Kavanaugh’s nomination. On Wednesday, she issued a statement rejecting an assertion that Dr. Ford had coached her on how to take a polygraph test. The assertion was made by a former boyfriend of Dr. Ford in a letter to the Senate Judiciary Committee.

—Alexandra Berzon contributed to this article.

Write to Natalie Andrews at Natalie.Andrews@wsj.com, Rebecca Ballhaus at Rebecca.Ballhaus@wsj.com and Sadie Gurman at sadie.gurman@wsj.com