Is Oksana Grigorieva Trying to Extort Money From Mel Gibson?

L.A. authorities investigating whether Oksana Grigorieva tried to extort money.

July 21, 2010 — -- The tables might be turning in Mel Gibson's ongoing battle with ex-girlfriend Oksana Grigorieva

The Los Angeles Sheriff's Department is looking into whether Grigorieva may have tried to extort money from Gibson in connection with audio recordings of their arguments leaked online and her allegations of domestic abuse, department spokesman Steve Whitmore told reporters today. He declined to comment further on the nature of the investigation.

Detectives obtained the recordings in a closed-door family court session last week. Gibson and Grigorieva currently are battling for custody of their 8-month-old daughter, Lucia.

Yet another tape leaked online Tuesday. In it, Grigorieva accuses Gibson of hitting her and Lucia, who she was holding in her arms.

The tape is the sixth recording purportedly of the actor's expletive-laced, ranting phone calls with Grigorieva that have been posted by RadarOnline.

In response to Grigorieva's allegations that he hit her and that he is mentally unbalanced, a man, presumably Gibson, replies, "No one will believe you."

"You hit me, and you hit her while she was in my hands! Mel, you're losing your mind. You need medication," Grigorieva tells him in the new excerpt.

When the man claims that she has used him for money, Grigorieva maintains that she signed a document giving up her claim to his fortune.

As in one of the earlier tapes, the man presumed to be Gibson tells her she will be raped because of her promiscuous appearance.

"If you get raped it's your fault, for starters," the man says. "Showing off your fake t**s! Like they're some special deal? How much did they cost, those fakers?"

The sixth tape was the latest salvo in the Mel Gibson saga. Last week, lawyers for the actor and Grigorieva faced off in family court.

Leaving the courtroom Thursday, they offered no clues about the custody hearing for the 8-month-old Lucia. According to TMZ.com, Gibson still has visitation rights.

The next day, RadarOnline posted a photo of Grigorieva taken after Gibson allegedly punched her in January showing her teeth clearly broken and her lips swollen.

The California court session came as the fifth audiotape was released online. In it, a man, presumably Gibson, slams Grigorieva for being a user and says he's broke because of her.

"I don't have any f***ing money. I have to support you and everybody else. I have to sell paintings," he growls. "I've spent too much f***ing money on you."

Grigorieva replies, "How much money do you spend on me? You don't spend more money on me than anybody else."

The man then says, "I've spent more than $5 million on you!"

The Associated Press and Reuters news service contributed to this report.