By Sara Sidner, CNN

(CNN) -- A grand jury has been convened in Cook County, Illinois, in connection with new allegations against singer R. Kelly, according to two sources close to the case.

This comes on the heels of attorney Michael Avenatti announcing last week that he had handed over to the State's Attorney's office a videotape that he says shows Kelly engaging in sex acts with an underage girl.

The Cook County State's Attorney would not confirm the grand jury proceedings or the existence of any new investigation. The office had previously encouraged any alleged victims of R. Kelly to come forward.

Steve Greenberg, an attorney for R. Kelly, told CNN on Monday he had not been notified of a grand jury.

"No one from law enforcement has contacted me or my client regarding any potential investigation," Greenberg said. "Certainly they are aware that I am representing him so if there were any reason to speak to him I would suspect they would have reached out to me."

"Grand jury proceedings are, by law, supposed to be secret, so to the extent people are commenting on what may or may not be going on today are possibly violating the law. Still, I can tell you that I am unaware of any proceedings," Greenberg said.

CNN has seen the VHS tape that appears to show Kelly having sex with a girl who refers to her body parts as 14 years old. Avenatti, who is representing a man he calls a whistleblower against Kelly, says he handed the tape to the Cook County State's Attorney's Office in Chicago last weekend.

"My client knows the identity of the girl and R. Kelly. He identified the two of them on the videotape. He worked for and has known R. Kelly for decades and he met the girl on a number of occasions," Avenatti said.

Greenberg, Kelly's attorney, told CNN after the tape had been handed over that he was not aware of it.

"We are unaware of any new information involving Mr. Kelly," he told CNN. "We have not been contacted by anyone. We have not been informed about any new information by anyone and we have not been contacted by law enforcement."

Tandra R. Simonton, chief communications officer for the State's Attorney's Office would not "confirm or deny an investigation" when the tape was reported last week.

What's on the tape

The newly unearthed footage, which lasts 42 minutes and 45 seconds, is clear and explicit.

There are two scenes on the video: one apparently in a living room and another in a bedroom. A naked man who appears to be R. Kelly is seen performing multiple sex acts with the girl. She is heard calling him "daddy" multiple times.

It is impossible to know her age just from the video. They both refer to her "14-year-old p*y." Six times the girl refers to her genitalia as 14 years old.

At one point, the man asks the girl to urinate. After she does, he urinates on her.

What is on the video mirrors some of the alleged acts for which Kelly was arrested for child pornography in 2002, when he was 35, and then acquitted six years later.

That case centered on another video involving a man having sex with a girl who prosecutors said was as young as 13 years old, media reports said.

Much was made at the trial about the identity of the man on the tape and whether an identifying mole on Kelly was visible on that video.

In the new video reviewed by CNN, a small mole can be seen on the man's back just to the left of his spine.

Kelly has been associated with claims of sexual misconduct with minors and other crimes for more than two decades. He has been sued by multiple women accusing him of having sex with them when they were underage. He has denied the accusations and all cases, with the exception of the trial where he was acquitted, have been settled out of court.

And while he is one of the most successful R&B acts in history, there has been a growing movement against him.

Music industry colleagues and former fans backed a #MuteRKelly campaign to stop his music being played.

In July 2017, Buzzfeed published an explosive article outlining claims that Kelly was holding a group of adult women against their will as part of what some of their parents say was a "cult."

A group of people cited in the article claimed that their daughters, ages 18 to 31, were a part of an entourage of at least six women attached to Kelly.

Joycelyn Savage, one of the young women, denied those claims and asked her parents, via a video shared with TMZ, to stop speaking out about her relationship with Kelly.

In January 2019, the release of a docuseries called "Surviving R. Kelly" on Lifetime television helped boost the public campaign against him.

In that series women said they were kept in abusive sexual relationships.

After the series aired, Cook County State's Attorney Kim Foxx urged potential victims or witnesses to speak to police.

At the same time, Kelly's attorney, Greenberg, told CNN that his client "has done nothing wrong ... Someone with an agenda has done a hit piece," Greenberg said of the docuseries. "(Kelly's) out in public. He's not hiding. There's no secret compound with sex slaves."