Source of Gibson Tapes Revealed?

How did RadarOnline nab the leaked Mel Gibson rants that have become so infamous? Several sources close to the case have told The Hollywood Reporter that it was the sister of Mel's ex-girlfriend, Oskana Gregorieva, who shopped around the audio tapes to tabloids before finally selling them to RadarOnline. "I suspect that if the authorities look at the sister, they'll find a wire transfer or a check to her from the website," one source tells The Hollywood Reporter. The sister, Natalie, was supposedly turned down by all the tabloids she approached because she wanted them to buy the tapes without first hearing them. If it turns out that Oksana requested that her sister sell the tapes, she could be found in contempt of court—in addition to rumored charges of extortion.