The autopsy didn't prove that he had his hands up, or that he didn't have his hands up. It would be exceptionally difficult (read: impossible) to show the positioning of his body based simply on the location of entry & exit wounds. The real world is not quite as simple as, say, CSI.
To even things out, why didn’t other redskin morons (dressed in police uniforms) run onto the field with guns shooting the others as they stole cigars and bull-rushed them?