Los Angeles (CNN) -- Seven alleged Los Angeles street gang members are charged with kidnapping and robbing a man who testified in court that they were after a Shaquille O'Neal sex tape he had.

Los Angeles prosecutors said they have not verified the sex tape, purportedly showing the retired basketball star having sex with several women, actually exists.

The alleged victim is Robert Ross, who said he was a member of the defendants' Main Street Mafia Crips Gang before he became a music promoter.

Ross testified at the defendants' preliminary hearing Monday that the gang members kidnapped him at gunpoint on Sunset Boulevard in West Hollywood, California, the night of the 2008 Grammy Awards.

They allegedly took him to the Los Angeles home of lead defendant Ladell Rowles.

"Defendant Rowles escorted victim Ross to a back room where he struck him with his handgun," the criminal complaint said.

The men took Ross' diamond chain, Rolex watch, diamond earrings and $15,000 in cash, the complaint said.

Ross, while on the witness stand, said it was then they demanded he hand over the videotape of O'Neal having sex with several women.

He testified that O'Neal knew through a mutual acquaintance that he had the videotape.

Ross, who said he was friends with O'Neal, testified that he tried to place music groups with O'Neal's record label.

A prosecutor said O'Neal is not involved in the case.

O'Neal did not immediately respond to a CNN request for comment about the allegations in the case.

He recently announced his retirement as a pro basketball player after 19 years in the NBA.

The preliminary hearing, which began last week in Los Angeles Superior Court, was continued until next month.