Mel Gibson Tapes: Evidence of Tampering, Editing By Oksana Grigorieva?

His vile rants have forever altered people's perception of him, but Mel Gibson's lawyers claim the now-infamous tapes of his outbursts were tampered with.

The actor's legal team says it has hard evidence that the four tapes (and counting) Oksana Grigorieva secretly recorded were tampered with and edited.

If true, it's still Mel ranting like a sexist pig, making death threats and racial slurs, and demanding to be orally serviced before burning down her house.

But it may make the tapes inadmissible in a court of law.

The L.A. County Sheriff's Department will have to authenticate the Mel Gibson tapes before handing over the domestic violence case to the D.A.'s Office.

That could take some time. Gibson faces investigation by authorities for allegedly attacking Oksana Grigorieva - while she carried their daughter no less.

Mel's lawyers deny he physically attacked Oksana in any way, and will present evidence to the Sheriff's Department that the tapes have been altered.

They say they have "concrete forensic evidence of tampering" with the tapes, including editing, though it is unclear if Oksana is the supposed culprit.

Grigorieva recorded Gibson's rants, but denies she is the person leaking them to various celebrity news outlets this week ... but who else could it be?

"We are not aware of any presentation Gibson's lawyers are making, but are not surprised they would make such unfounded claims," her lawyers said.

In addition to the criminal investigation against Mel, there is the matter of custody over Lucia. Grigorieva wants a judge to strip Mel of custody.

She will use tapes as evidence Mel is a danger to the child, and the authenticity of the tapes will almost certainly be raised by Mel's attorneys.

Authentic or not, follow the jump to hear all four Gibson tapes ... (thehollywoodgossip)