A new development surfaced Monday in the R. Kelly case. TMZ reports that a grand jury has been convened to hear evidence against the embattled singer after a new sex tape surfaced allegedly showing the singer having sex with an underage girl.

According to the website, sources connected with the Cook County State Attorney’s investigation said several women who claim to have been sexually abused by Kelly flew out to Chicago to speak with the prosecutor.

READ MORE: New R. Kelly Sex Tape: Michael Avenatti claims he has new 45-minute video showing singer sexually abusing underage girl

Attorney Michael Avenatti announced last week that he had possession of a sex tape that allegedly showed Kelly having sex with an underage girl, and on Saturday he took to Twitter to confirm that a third tape exists of the R&B hitmaker sexually abusing a female minor.

Avenatti has turned over the newly surfaced sex tapes to the Cook County State’s Attorney’s Office in Chicago that could soon lead to an indictment of Kelly in Illinois.

Both tapes are not the same as the infamous 27-minute footage from 2002, which allegedly showed him urinating on a teen girl believed to be 14 years old. Kelly was charged with 14 counts of child pornography in 2008 but found not guilty on all counts.

Avenatti, best known for representing porn star Stormy Daniels in a lawsuit against Donald Trump, tweeted on Thursday that he has been working overtime to bring down the superstar since April, noting that he plans to give all evidence to Chicago’s Cook County State Attorney Kim Foxx.

“We will continue to work tirelessly to ensure that this predator is brought to justice,” he tweeted. “As a father of two teenage girls myself, I have the utmost faith and confidence in Ms. Foxx and her staff to ensure justice is done.”

READ MORE: Parents who say R. Kelly is holding their daughter captive plead for her release ‘You need to turn yourself in, let these girls go’

Avenatti, who is representing an unnamed client who claims to know the identity of the girl in the tape, is so determined to see Kelly prosecuted that he is reportedly working on the case without pay, according to Newsweek. He even claims in a Twitter post that the singer tampered with evidence in the 2008 child sexual abuse case in which he was acquitted.

“Due to the importance of ensuring justice is finally done in this matter and because we are deeply concerned that Mr. Kelly has not been held accountable for his sexual abuse of young African-American girls, whom are especially vulnerable, we have done so on a pro bono basis,” his Thursday statement said, per Newsweek. “Importantly, it has now resulted in the discovery of significant new evidence conclusively establishing Mr. Kelly’s illegal sexual assault of young girls.”

Attorney Gloria Allred, known for representing women in sexual harassment and women’s rights cases, said over the weekend that the teen alleged to be shown on the new tape might be her client, but Avenatti said he has confirmed that is not true.

READ MORE: Gloria Allred says teen shown on the new R. Kelly tape may be her client

Kelly’s attorney, Steven Greenberg told TMZ that the report that a grand jury is convening is false. “I am unaware of any ‘special’ grand jury being convened to look into R. Kelly. There is no record of any such proceedings, and no need for them. The report is false.”