You may have heard of the "Alien Autopsy" film, which purports to show an autopsy on the corpse of an alien found at the "flying saucer crash" site near Roswell, New Mexico. The film appeared in 1995, alleged to have been hidden away for decades by the cinematographer who filmed it. It was shot (supposedly) in 1947 on 16mm black-and-white movie film with a Bell & Howell Filmo camera. Remember, creatures of the 21st century, that video recording did not exist in 1947; movie film was the only moving picture medium.
The opinion of CSICOP at the time is interesting. Read their story from 1995. A real surgeon who saw the film wrote a blistering review of the film's credibility. Here's another story about the hoax.
Defenders of the film insisted that it is genuine, while many others showed evidence that it is a hoax. Fox, the network that aired the film, seems to have had the last word. Check out this reference. This seems to settle it.
New Mexicans for Science and Reason (nmsr.org) Annual Best and Worst Awards for 2006
The whole idea of UFO investigation, if indeed there is any scientific value in it at all, is not helped by hoaxes such as this.