The mystery deepens. An eyewitness to the shooting states that "he had someone with him". He also stated that the second cannister of gas "did not come from his side". According to Michael Kelly's article in the business insider at a July 20 press conference Chief Dan Oates said investigators were confident that James Holmes acted alone and that he was "apprehended outside his White Hyundai parked in the back of the theater..."
BUT - the article goes on to state that skeptics point to an exchange in the police transmissions as evidence that Holmes was found in his LOCKED car with a gas mask on and heavily drugged and it appears they were prepared to carry him out on a white stretcher board (pictured underneath the car). Three minutes after Holmes was supposedly detained in/by his car, an officer says "One of the shooters might be wearing a white and blue plaid shirt" and the dispatcher responds "Copy, outstanding shooter possibly wearing a white and blue plaid shirt."
Factor in that a second gas mask was found hundreds of feet from Theater 9's emergency exit and Holmes' car. Keep in mind that Holmes was immediately arrested in the back of the theater 90 seconds after the first 911 call was made and was found wearing a different gas mask.
Now that the Holmes case is sealed the records can not be examined and compared to the information that we currently have.
Why was there a second gas mask?
Was there a second shooter?
Does it seems that Holmes was conveniently left to take the "rap"?
Who could have been behind this?
Will we ever know what really happened?
UPDATE (August 27, 2012): An interesting video that has edited in police transmissions. Aurora Colorado Theater Shooting - The James Holmes Conspiracy - Part 1/4