Just a thought... but if, it was in his waistband/holster/retention device, and he was told to 'put it on the ground' as some ear witnesses have said...
...wouldn't that mean that the officers would have been telling him to remove it and place it on the ground?
If you tell me to put something in my pocket on the ground, well, I have to reach down, and remove it from my pocket first to comply, wouldn't I?
Someone standing there with guns drawn on them may not be in complete control of all their faculties, and was literally, just trying to do what the officers told him to....
I know that I'd be pretty, shaken, if I were in that situation, and would be trying to comply with every command yelled at me by the officers.
Just a thought.