First off, this thing was videotaped by about 100 camera's. This link shows a different angle, as well as the aftermath.
http://www.youtube.com/watch?v=V8ndctwAJmU
The kid's actions are nothing short of bizarre. You can see that he is being led up the stairs, and seems to attempt an escape of some-sort, which is what led to the tasing. Then they show the aftermath, and instead of taking him somewhere, they just kind of hang out in the hallway. While hand-cuffed, and after being tased, he asks about his book? Why in the world would he be so interested in the whereabouts of his book with what he was going through? This whole incident just doesn't "smell" right!