Violet Kowal, the Polish porn star who had an affair with Mel Gibson while Oksana Grigorieva was pregnant, has shocking new audio tapes and has emerged as a witness being courted by the two feuding camps, RadarOnline.com has exclusively learned.

Oksana's audio of Gibson's ranting and threats became a national talking point when obtained exclusively by RadarOnline.com this summer.

And now, Kowal has a controversial new audio tape that directly affects the case.

Everything old is new again in the Oksana Grigorieva’s bitter legal battle with Lethal Weapon star Mel Gibson.

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She recently hired Sorrrell Trope as her new lawyer – but RadarOnline.com is reporting exclusively that she first met with him – and rejected hiring him – the day after failed mediation talks in May.

“Oksana was furious at how she was treated during the mediation,” said a source, with intimate knowledge of the case.

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“At the time, she was being represented by Eric George, but after the talks broke down, Oksana met with Sorrell Trope and then celebrity divorce attorney Stacy Phillips.

“Oksana didn’t sign with either of them because she said they were asking for a $20,000 retainer before commencing work on the case.

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“In the end, she told George that she wanted new counsel and he ultimately introduced her to Manley Freed and Marci Levine.”

However, Grigorieva axed Freed and Levine on Monday and appointed Trope to the case, who has represented celebrities including Anna Nicole Smith and Britney Spears.

EXCLUSIVE PHOTOS: Oksana Grigorieva's Broken Veneers

It is the second time that the Russian-born singer-songwriter has changed legal teams during the course of the child custody case.

Grigorieva is seeking to increase the monthly child support payments that she receives from Gibson.

Comment is being sought from Trope.

Oksana Grigorieva has beefed up her legal team with a top criminal and civil attorney, RadarOnline.com has exclusively learned.

With no settlement looming in the bitter fight with Mel Gibson, Oksana is digging in for a fight and appointed James W. Spertus, a former federal prosecutor and an experienced trial attorney who specializes in civil and criminal litigation, to her growing team.

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As we revealed, Oksana had been lawyer shopping and previously met with civil rights campaigner Lisa Bloom and Mark Lane, who wrote the JFK conspiracy book Rush to Judgment.

She also met with two other firms, we understand.

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Spertus joins power lawyers Manley Freid and Marci Levine in the Russian musician's corner.

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He previously served for seven years as an Assistant U.S. Attorney in the Central District of California.

According to his law firm biography, Spertus helped found the office's Computer Crimes and Intellectual Property Section and tried criminal cases involving trade secret theft, computer intrusions and intellectual property theft.

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He also served as Vice President at the Motion Picture Association of America.

Oksana, 40, has told investigators Mel, 54, exploded in rage January 6 at his Malibu mansion and punched her more than once as she held their infant daughter Lucia, before threatening to kill both of them.

She has told cops a blow to her mouth knocked one veneer off a front tooth and cracked another, while the fist left her bloodied and bruised.

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On Tuesday, Team Oksana met at Freid and Levine's Los Angeles office after two successive days of hearings before a Los Angeles judge overseeing the case.

Oksana is considering filing a possible civil complaint against the Lethal Weapon star, who has accused Oksana of trying to extort money from him after recording vile and abusive telephone conversations he made.

EXCLUSIVE PHOTOS: See The First Photos of Mel and Oksana In a Passionate Embrace On The Beach

In an interview with RadarOnline.com, Oksana denied the claim and said her ex-lover was "trivializing" domestic violence.

"What is unfair is that by standing up to somebody and speaking up, I'm being victimized all over again," she told us, in an emphatic denial that she tried to blackmail the Oscar-winning actor/director.

"I have never extorted anything from him... There's no proof of any kind. It's all false information that he's feeding the press. It's a smear campaign."

Mel's camp had also claimed Oksana edited the now infamous rants - an allegation she has also denied.

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MEL AUDIO TAPE #1:  Mel’s Racist Rant

MEL AUDIO TAPE #2: Mel Gibson Admits Hitting Oksana, Threatens To Kill Her

MEL AUDIO TAPE #3: Another Mel Gibson Slur Caught On Tape In Crazed Rage

MEL AUDIO TAPE #4: Out Of Control Mel Gibson Says He'll Burn Down House After Demanding Sex

MEL AUDIO TAPE #5: Mel Gibson Completely Loses It: 'B*tch, C*nt, Wh*re, Gold Digger!'

MEL AUDIO TAPE #6: The Tape That Could Destroy Mel: "No One Will Believe You", He Says After She Charges: "You Hit The Baby"

MEL AUDIO TAPE #7: Mel Gibson's Twisted Rant Includes Jealous Rage Over Timothy Dalton

Mel Gibson offered the mother of his illegitimate child almost $20 million to settle their bitter custody battle before it imploded, RadarOnline.com has exclusively learned.

But Oksana Grigorieva is rejecting the massive cash settlement because she would have had to share custody of their eight-month-old daughter Lucia.

"Mel wanted Oksana to sign an agreement that would have meant Lucia spends 80 per cent of her time with her mother and the remaining 20 per cent with her father," said a source, familiar with the case.