A man who said he was cleaning out an old videotape collection found what he thought was a recording of R&B singer R. Kelly in concert, but instead turned out to show a man who appeared to be Kelly sexually abusing girls, he and his attorney said Sunday.

The man then turned the tape over to law enforcement, according to attorney Gloria Allred. She and her client, Gary Dennis, would not discuss the specifics of the tape during a news conference in New York. But Allred said it appears to show a separate incident from the aggravated sexual abuse charges Kelly faces in Chicago, though she acknowledged she could not be "100 percent certain" that the man in the tape is Kelly.

Dennis, an assistant at a nursing home, said he was cleaning out a box of old VHS tapes in his Pennsylvania home recently when he found the footage. Dennis said he has never met Kelly and doesn't know how the tape came to be in his possession. He said that because the tape also has a sports game on it, he believes it may have come from a friend.

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"To my shock and surprise, R. Kelly appeared to be on the tape, but not in concert," Dennis said. "Instead he was sexually abusing underaged African-American girls."

"I was disgusted and horrified when I saw that," Dennis said.

Last month, Kelly was charged with 10 counts of aggravated criminal sexual abuse. The charges involve four women, three of whom were underage at the time of the alleged events. Prosecutors have said they video of Kelly abusing one of the girls.

In his interview with "CBS This Morning" co-host Gayle King, the singer denied the allegations and called his accusers liars.

Kelly has faced intense scrutiny for more than a decade, which was reignited in January after the six-part Lifetime docuseries "Surviving R. Kelly." It featured interviews with seven accusers and former members of his inner circle. They all said Kelly preys on vulnerable women and young girls.

Allred, who represents women who said they were abused by Kelly, said the tape from Dennis was turned over to law enforcement in the federal Eastern District of New York. She didn't say why it went to that venue. That office didn't immediately return requests for comment.

A Chicago police spokesman referred questions about Allred's news conference to the prosecutors handling the case. That office did not immediately return a call seeking comment. Steve Greenberg, an attorney for Kelly, also did not immediately return requests for comment.