As Ferris previously stated, his laptop hard drive blew up, due to a faulty center wing tank explosion. The FBI seized all cell phones that had video, and returned the phones to their owners - wiped clean to factory settings.
To address a couple of your points - not trying to be argumentative I too have been frustrated by the lack of transparency and here are some things I've found/thought for your consideration Skypilot.
The computer might have been booted off of a usb stick flushed down the toilet.
As far as the cell phone being taken and wiped by the FBI - I don't think that is true. If you have the stomach you should watch this video New York Times video time linewith the timeline as it happened pieced together from peoples phones who were there and taking video - warning this video is brutal to watch its the whole shooting start to finish. Normally wouldn't recommend anything from the times but I thought they did good work here.
My favorite crazy theory is something of the lines of an ocean 11 bank heist.
Then there was this weirdness - where the officer "accidently" dischared his firearm (shot his gun).
That saudi theory is quite full of holes - notice no time stamp on the Tropicana camera - those things all have time stamps - there are many more but it is a great attempt to tie eveything together.
It is outrageous that its being buried and I do believe there is some sort of cover up - I still have no idea what was really going on other than somebody put approx 900 rounds down range mostly into a crowd and the authorities have gone silent.