Did Mel Gibson Make Another Anti-Semitic Rant?

More questions continue to grow about Oksana Grigorieva, who is involved in an increasingly ugly custody battle with ex Mel Gibson.

On Friday, RadarOnline reported that Gibson, 54 -- who famously spewed anti-Semitic rants during his 2006 DUI -- once allegedly told her, "I want Jew blood on my hands," referring to a high-profile Hollywood figure. He said he wanted to take the person to the desert, strip them naked, cap their knees and leave them in the heat, according to Radar.

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TMZ.com reports that it heard the story was about its exec Harvey Levin, who apparently angered Gibson by breaking the news about his ugly DUI bust.

But TMZ insists that after investigating, the story had so many holes in it and proved to be "false."

Sources tell UsMagazine.com that Grigorieva's claims are a ploy for more custody — and cash. (Gibson's lawyer Stephen Kolodny tells Us the duo had reached an agreement in May that would lead to fifty-fifty custody.)

No word from reps for Grigorieva, 40, or Gibson.

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But authorities are currently investigating who leaked the now-infamous damaging recordings of Gibson spewing racist comments and threatening Grigorieva to the media.

According to The Hollywood Reporter, Grigorieva's sister younger sister, Natalie, may have played a key role. Several sources tell the site that she shopped around the tapes to media outlets before making the sale to Radar. Said one insider: "All the tabloids said no to the deal because they were asked to purchase the audio tapes before hearing them."

Added another, "I suspect that if the authorities look at the sister, they'll find a wire transfer or a check to her from the website. She and Oksana are very close."

If true, the Russian singer could be found in contempt of court.

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Authorities are currently investigating whether or not Grigorieva tried to extort money from Gibson. In a text message, Grigorieva allegedly told Gibson that the reason she recorded him was that "you broke your agreement with me," according to THR.

TMZ also reports that Grigorieva had a civil lawsuit ready to file against Gibson in May, in the event he failed to negotiate a custody and financial deal she considered fair.