Mel Gibson and Oksana Grigorieva

It has been speculated that the voice recording of Mel Gibson ranting and raving to his ex girlfriend and mother of his child could have been tampered with.

Lawyers for Gibson said they will be presenting evidence to the L.A. County Sheriff's Department including proof that the tapes have been altered.

The Sheriff's Department will need to authenticate the tapes before a case goes to the District Attorney's office.

This authenticity could take some time.

Lawyers fro Gibson's ex girlfriend, Oksana Grigorieva said  "We are not aware of any presentation Gibson's lawyers are making, but we are not surprised they would make such unfounded claims."

Oksana's lawyers were due in court on Thursday morning in L.A. to seek an order from a family judge to have Gibson's daughter removed from his custody.

The lawyers plan to use the tape- in which Gibson uses racially offensive and abusive language- as evidence that Gibson could harm the child.

A judge will admit tapes into evidence only if someone can authenticate that the tapes are true and correct copies of what was actually recorded.

However, in his own case, Gibson is seeking to hold Oksana in contempt of court after accusing her of leaking the secret audio tapes to the press, violating a restraining order.