Some evidence that the audio track of the recent Osamah Bin Laden video was laid down over an older video has been given.
If true, this manipulation would not in my view prove that the audio was fraudulent.
One problem is that the video would have to be awfully old to have Osama with a short black beard, and I don’t know of any old footage that looks like that.
The audio sounds like Osama to me.
See Barnett Rubin’s analysis of the new speech as a form of market rebranding on Bin Laden’s part.