Walker along with his girlfriend Tamara Eileen Diaz have been charged with a felony count of extortion, the Los Angeles County district attorney's office said Friday, reported TMZ online.
Walker demanded USD 5 million from Wonder to keep him from going to the media with a tale of incest. When his initial request was declined, the 38-year-old lowered his demand to USD 10,000.
It was said that he got arrested by undercover cops, who posed as Wonder's representative, after signing a document that stated his accusations were false.
Both Walker and Diaz have pleaded not guilty to the charge, and are still being held in jail awaiting a preliminary hearing that is scheduled for Wednesday, May 16 at the downtown Criminal Courts Building.
A spokeswoman for the District Attorney's Office said that the hearing will determine if they will have to stand trial on the charge.
Walker and Diaz don't have a clean sheet record. When arrested, both of them were on probation. Walker pled no contest to grand theft in May 2011, while Diaz got charged with possession of marijuana with the intent to sell back in February 2011.