Mel Gibson

Could Mel Gibson pull an it-wasn't-me defense?

Since Friday, horrified listeners have heard recorded phone calls in which a man who sounds like the actor uses racial slurs, tells the mother of Gibson's child she deserved a recent battering, and threatens to bury her in a rose garden. A fourth call, released Wednesday, includes demands for oral sex and a threat to "burn the g------ house down."

The tapes: Day 3

All of which might seem career-ending for the Oscar-winning director of Braveheart and The Passion of the Christ — unless, somehow, it isn't Gibson's voice on the calls.

For that to be true, Gibson would have to be the victim of an extremely complicated and unusual setup — as well as an extraordinarily skillful one.

Gibson, who's under investigation for alleged domestic violence against Oksana Grigorieva, says she threatened to leak damaging recordings if he didn't pay her. Gibson says she also made false abuse claims. A rep for the actor declined to comment to TVGuide.com on whether Gibson is the one in the recordings.

Man who sounds like Gibson tells ex she "deserved it"

While movies are full of tapes spliced and edited together to make innocent people look bad, such recordings rarely succeed in real life because they are so easy to discredit, says James A. Griffin, an audio authentication expert who has testified in several trials and consulted for CSI: Miami.

His cursory opinion of one of the tapes, based on a recording on RadarOnline.com, is that the exchange is real.

"This is a conversation that actually did take place," he told TVGuide.com. "It is not a cut-and-paste job."

Mel Gibson reportedly dropped by agency after angry recording leaks

The question, then, is whether the person who sounds like Gibson really is Gibson. The racist remarks are similar to those the actor made against Jews after his 2006 drunken driving arrest, but those remarks could make the actor more vulnerable to a false impersonation.

"There's a lot of sound-alike voices," says Tom Owen, an audio expert who has examined recordings of the Kent State shooting and Osama bin Laden. "I'm sure Hollywood's got lots of people that can sound like Mel Gibson if they want to."

The problem is that Gibson's voice can't be authenticated from the recordings circulating online. Owen and Griffin agree that experts would need to listen to an original copy to investigate, and the calls the public has heard do not seem to be originals, they said. (At one point in the third tape, for example, a name is deleted.)

Griffin said that given the similarities between Gibson's voice and the one on the tapes, the only way for the actor to prove he wasn't the one speaking would be to submit to a comparison.

It would be quite a vocal workout for the actor, given the ranting, roaring nature of the calls.

"The voice is deformed. The actual vocal cavity is not processing properly when you're yelling or screaming or intoxicated," Owen said. "The voice is not the normal Mel Gibson that you hear in the movies."

On that point, everyone can agree.