Warning: this story contains sensitive, graphic details related to sexual abuse

Lawyer Gloria Allred says a tape has been turned over to police by a client, which appears to show R&B singer R. Kelly sexually abusing girls.

"They assume that the girls were underage because they were not fully developed," Allred said at a news conference held Sunday in New York City. "R. Kelly was the only man seen on the tape."

Allred's client, Gary Dennis, said at the news conference that he doesn't know the musician personally and doesn't know the origins of the tape. It was found in a box in his home while he was going through a collection, he says.

Origin of tape unknown

"As a parent, it is very disturbing to know that any adult … would engage in sexual acts with a child," said Dennis, who was seated alongside Allred and his wife, Sally. "There can be no justification for anyone to do what I saw on this tape."

Gary and Sally Dennis, clients of lawyer Gloria Allred, say a video allegedly showing R. Kelly sexually abusing young girls, was found in their home but its origin is unknown. 0:50

Kelly is facing 10 counts of aggravated sexual abuse pertaining to four women, including three who were minors when the alleged abuse occurred. He has pleaded not guilty to the charges and has denied any wrongdoing. In an interview last week with CBS This Morning, the I Believe I Can Fly singer told Gayle King he had never had sex with a minor and became increasingly agitated and emotional while answering questions pertaining to the allegations.

The latest tape is the third to have been presented in the ongoing case — two other videos alleging similar acts are already in the possession of prosecutors.

More video possible

While Allred would not say if she had viewed the alleged tape herself, she said the city and state are not identifiable in the contents. She also said it was unclear whether the alleged victims knew they were being filmed and would not disclose the length of the video.

In this March 5 photo, Kelly gestures while making a point during an interview with Gayle King on CBS This Morning, where he became increasingly agitated and emotional when asked about the allegations. (Lazarus Jean-Baptiste/CBS/Associated Press)

Allred, who represents women who say they're victims of R. Kelly's alleged abuse, said it's likely there may be more video out there.

"I have been contacted by others with knowledge of other tapes," she said, adding any further information remains confidential.

"There may be people out there profiting from these tapes," she said.

Last week, Kelly was sent to jail by a judge after he couldn't pay $161,000 US in back child support. On Saturday, the payment was made on his behalf by an individual who remains anonymous, and Kelly was released.

Allred said her client turned over the tape to authorities because "the protection of children is paramount."