AceShowbiz - Oksana Grigorieva is facing her own police investigation into allegations she attempted to extort $10 million (6.6 million pound sterling) from her ex-boyfriend Mel Gibson to keep recordings of his vile telephone rants private. Secret audio tapes allegedly featuring an enraged Gibson hurling expletives and abuse at the Russian singer emerged days after Grigorieva accused her ex of hitting her during heated arguments before they split earlier this year.

Los Angeles police have since launched a domestic violence investigation into her claims as the former couple fight over custody of their baby girl, Lucia. The "Braveheart" star's legal representatives have denied the attack allegations and have since countered that Grigorieva tried to bribe Gibson for a big cash payout in exchange for the audio footage.

Gibson's attorney, Blair Berk, formally filed the complaint with the Los Angeles County Sheriff's Department on Tuesday, July 21 and the lawyer is believed to have evidence to prove the extortion claims. Sheriff's spokesman Steve Whitmore tells TMZ.com, "Extortion allegations have been brought to our attention and we are certainly going to be looking at that."