Mel Gibson”s ex facing probe in blackmail claim

Detectives are investigating Mel Gibson’s ex-girlfriend Oksana Grigorieva over allegations that she tried to blackmail the actor.

Los Angeles sheriff”s spokesman Steve Whitmore confirmed that a probe was underway, but he didn’t give any details of the investigation.

Grigorieva, 40, is accused of trying to sell Gibson, 54, tapes of bitter fights between them, threatening to go public if he refused to buy them, reports the New York Daily News.

RadarOnline has been posting excerpts of the tapes for two weeks, pulverizing the ‘Braveheart’ star”s battered reputation.

Gibson and Grigorieva are locked in a bitter battle for custody of the child, Lucia.