When Sen. Chuck Grassley referred attorney Michael Avenatti and his client Julie Swetnick to the Justice Department for criminal investigation Thursday, he cited Swetnick's interview with NBC News as evidence the two were trying to mislead the Senate Judiciary Committee.

In the NBC News interview that aired on Oct. 1, Swetnick back-tracked on or contradicted parts of her sworn statement where she alleged she witnessed then-Supreme Court nominee Brett Kavanaugh "cause girls to become inebriated and disoriented so they could then be 'gang raped' in a side room or bedroom by a 'train' of boys."

NBC News also found other apparent inconsistencies in a second sworn statement from another woman whose statement Avenatti provided to the Senate Judiciary Committee in a bid to bolster Swetnick's claims.

In the second statement, the unidentified woman said she witnessed Kavanaugh "spike" the punch at high school parties in order to sexually take advantage of girls. But less than 48 hours before Avenatti released her sworn statement on Twitter, the same woman told NBC News a different story.

Referring to Kavanaugh spiking the punch, "I didn't ever think it was Brett," the woman said to reporters in a phone interview arranged by Avenatti on Sept. 30 after repeated requests to speak with other witnesses who might corroborate Swetnick's claims. As soon as the call began, the woman said she never met Swetnick in high school and never saw her at parties and had only become friends with her when they were both in their 30s.

When asked in the phone interview if she ever witnessed Kavanaugh act inappropriately towards girls, the woman replied, "no." She did describe a culture of heavy drinking in high school that she took part in, and said Kavanaugh and his friend Mark Judge were part of that group.

In a statement Thursday about his referral of Swetnick and Avenatti for a criminal investigation, Grassley said, "When a well-meaning citizen comes forward with information relevant to the committee's work, I take it seriously….But in the heat of partisan moments, some do try to knowingly mislead the committee. That's unfair to my colleagues, the nominees and others providing information who are seeking the truth."

Avenatti responded in a statement to NBC News saying, "Senator Grassley has just made a major mistake. Let the investigation into Kavanaugh and his lies begin."

Kavanaugh and Judge denied the allegations leveled by Swetnick and other women. Avenatti, asked about the inconsistencies within the second woman's account, said: "It is a sworn declaration that she read and signed and repeatedly stood behind."

Senate Judiciary Committee Chairman Chuck Grassley, R-Iowa, speaks to reporters as he leaves the chamber following a procedural vote to advance the confirmation of Supreme Court nominee Brett Kavanaugh, at the Capitol in Washington on Oct. 5, 2018. J. Scott Applewhite / AP

According to the second woman's declaration that Avenatti provided to the Senate Judiciary Committee, she said: "During the years 1981-82, I witnessed firsthand Brett Kavanaugh, together with others, 'spike' the 'punch' at house parties I attended with Quaaludes and/or grain alcohol. I understood this was being done for the purpose of making girls more likely to engage in sexual acts and less likely to say 'No.'"

The statement also said that Kavanaugh was "overly aggressive and verbally abusive to girls. This conduct included inappropriate physical contact with girls of a sexual nature."

But reached by phone independently from Avenatti on Oct. 3, the woman said she only "skimmed" the declaration. After reviewing the statement, she wrote in a text on Oct. 4 to NBC News: "It is incorrect that I saw Brett spike the punch. I didn't see anyone spike the punch...I was very clear with Michael Avenatti from day one."

When pressed about abusive behavior towards girls, she wrote in a text: "I would not ever allow anyone to be abusive in my presence. Male or female."

Julie Swetnick Michael Avenatti / via AP

Shortly after tweeting out the woman's allegations on Oct. 2, Avenatti confirmed to NBC News that it was the same woman interviewed by phone on Sept. 30. But when questioned on Oct. 3 about the discrepancies between what she said in the phone interview and the serious allegations in the sworn declaration, Avenatti said he was "disgusted" with NBC News. At one point, in an apparent effort to thwart the reporting process, he added in the phone call, "How about this, on background, it's not the same woman. What are you going to do with that?"

After NBC News received text messages from the woman refuting some of the claims in the declaration, NBC reached out again to Avenatti, who defended the declaration.

"I have no idea what you are talking about," he said in a text. "I have a signed declaration that states otherwise together with multiple audio recordings where she stated exactly what is in the declaration. There were also multiple witnesses to our discussions."

He sent a follow-up message moments later: "I just confirmed with her yet again that everything in the declaration is true and correct," Avenatti said. "She must have been confused by your question."

Roughly five minutes later, the woman sent a formally-worded text backing Avenatti. "Please understand that everything in the declaration is true and you should not contact me anymore regarding this issue," the text read.

But when reached by phone minutes later, the woman again insisted that she never saw Kavanaugh spike punch or act inappropriately toward women. She said she's "been consistent in what she's told Michael."

In a subsequent text on Oct. 5, she wrote, "I will definitely talk to you again and no longer Avenatti. I do not like that he twisted my words."