Sen. Bernie Sanders (I-VT) demanded in a letter to Senate Judiciary Chairman Chuck Grassley (R-IA) on Saturday that the FBI investigate Supreme Court nominee Brett Kavanaugh’s statements made under oath during Thursday’s hearing to see if he is telling the truth.

Lying to Congress is a federal crime. The FBI must examine the veracity of Kavanaugh’s statements under oath in addition to the sexual assault allegations against him. Kavanaugh's truthfulness with the Senate goes to the very heart of whether he should be confirmed to the court. pic.twitter.com/TsNOTm4fxK — Bernie Sanders (@SenSanders) September 29, 2018

“Lying to Congress is a federal crime,” Sanders tweeted Saturday morning. “The FBI must examine the veracity of Kavanaugh’s statements under oath in addition to the sexual assault allegations against him. Kavanaugh’s truthfulness with the Senate goes to the very heart of whether he should be confirmed to the court.”

Sanders wrote in the letter that the FBI must not only investigate the accusations made by California psychology professor Dr. Christine Blasey Ford, Debora Ramirez, and Julie Swetnick, but they should also look into Kavanaugh’s testimony before the Judiciary Committee.

“In order for the FBI investigation regarding Judge Brett Kavanaugh’s nomination to be complete, it is imperative the bureau must not only look into the accusations made by Dr. [Christine Blasey] Ford, Debora Ramirez and Julie Swetnick, it should also examine the veracity of his testimony before the Judiciary Committee,” Sanders wrote in the letter.

“A fundamental question the FBI can help answer is whether Judge Kavanaugh has been truthful with the committee. This goes to the very heart of whether he should be confirmed to the court,” Sanders’ letter continued.

The Vermont senator also called for the FBI investigation to take longer than one week, citing Senate Majority Leader Mitch McConnell’s decision to delay holding a hearing for Merrick Garland’s nomination to the Supreme Court for almost a year.

“If you are concerned with a delay in this confirmation process, remember that Senate Republicans refused to allow the Senate to consider Merrick Garland’s nomination to the Supreme Court for nearly a year,” Sanders wrote.

One of Kavanaugh’s accusers, Dr. Ford, testified before the Senate Judiciary Committee on Thursday, and Kavanaugh also testified before the committee responding to her allegations that he sexually assaulted her at a high school party in 1982.

The Senate Judiciary Committee voted Friday in an 11-10 party-line vote to send Kavanaugh’s confirmation to the Senate floor but decided to take into account Sen. Jeff Flake’s (R-AZ) call for a one-week delay on the floor vote so the FBI could conduct an investigation into the sexual misconduct allegations.

President Trump ordered the FBI to “conduct a supplemental investigation” into Kavanaugh that would last no longer than “one week.”