Earlier quoted context omitted.
In addition, I imagine a list of students who had finals in those buildings around that time also entered into the equation. Talking to the guy using tor at the time, who had finals at the time, is a no brainer.
he wouldn't have gotten nabbed in a court of law -- all you need is a motive.
I don't know if he used the Tor Browser Bundle, and if that is even all that clean from a forensic standpoint, but I certainly wouldn't trust it to conceal what I did.
Maaaybe he'd have a chance if he used a LiveCD that they could not find evidence of him ever having. That is a very strong "maybe".