Former FBI Director James Comey said Sunday that Supreme Court nominee Brett Kavanaugh's "obvious lies" about his high school yearbook hint at "bigger lies" that may be uncovered.

Comey wrote that FBI agents are up to the task of unearthing the truth of sexual assault allegations made by Christine Blasey Ford and others, and that he believes Kavanaugh's Thursday testimony could suggest trouble.

"Yes, the alleged incident occurred 36 years ago," Comey wrote in a New York Times op-ed, referring to Ford's accusation. "But FBI agents know time has very little to do with memory."

"They know every married person remembers the weather on their wedding day, no matter how long ago. Significance drives memory. They also know that little lies point to bigger lies," he wrote. "They know that obvious lies by the nominee about the meaning of words in a yearbook are a flashing signal to dig deeper."

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On Thursday, Kavanaugh told members of the Senate Judiciary Committee that apparent sexual references in his self-written yearbook biography actually had innocent and lesser-known definitions.

Kavanaugh said that the term "devil's triangle" referred to a drinking game, rather than a sexual threesome with two men, and that the word "boof" referred to flatulence rather than rectally imbibing alcohol.

His explanations were unconvincing for Sen. Sheldon Whitehouse, D-R.I., who accused Kavanaugh of lying.

"I don't believe 'boof' is flatulence, I don't believe a 'devil's triangle' is a drinking game, and I don't believe calling yourself a girl's 'alumnius' is being her friend,” Whitehouse said Friday as the Judiciary Committee prepared to vote on Kavanaugh's nomination.

[Byron York: Ralphing, fart jokes, and the FFFFF-word: Sen. Whitehouse's star turn at Kavanaugh hearing]

The committee approved Kavanaugh in a party-line vote, but President Trump requested a one-week FBI investigation Friday after Sen. Jeff Flake, R-Ariz., indicated he would be uncomfortable with an immediate Senate floor vote.

Comey warned in his op-ed that Kavanaugh's yearbook testimony may have more serious meaning as FBI agents interview potential witnesses linked to three alleged sexual assaults involving Kavanaugh.

"Once they start interviewing, every witness knows the consequences. It is one thing to have your lawyer submit a statement on your behalf. It is a very different thing to sit across from two FBI special agents and answer their relentless questions," Comey wrote. "Of course, the bureau won’t have subpoena power, only the ability to knock on doors and ask questions. But most people will speak to them. Refusal to do so is its own kind of statement."

Ford alleges that Kavanaugh pinned her to a bed, attempted to remove her clothing, and covered her mouth in a manner that made her fear for her life when she was 15 years old and he was 17. Four people identified by Ford as attending the 1982 gathering, including Kavanaugh, said they have no recollection of the event.

Former Yale University classmate Deborah Ramirez alleges that Kavanaugh exposed himself to her when he was 18 years old, forcing her to touch his penis without her consent. A third accuser, Julie Swetnick, alleges he was present when she was "gang raped."

Comey, a Republican former Bush administration official, was selected by former President Obama to lead the FBI. Trump fired him last year, and has provided inconsistent public explanations of his decision.

The former FBI director took a swing at Trump in his op-ed, writing that "the president routinely attacks the FBI because he fears its work."