Line was FSU +4.5 right before tip or is being reported as that by many. If Hamilton bet on FSU to cover he had the bet won thus the no free throws. Instead of trying to actually win he conceded the game to ensure his bet won. That's what it looks like to a lot of people right now at least.
So let me get this straight... Leonard Hamilton is a gamblin' man who wanted his team to get close to winning, but not quite win, so he took the 4'. Why wouldn't he just take Michigan and tank the whole game? That is much easier and wouldn't have given him a heart attack... what if one of his players had accidentally fouled? The officials could have not been aware of the scheme as well and anticipated a foul, also foiling it. Did you listen to Hamilton after game? Does he come off as a game fixing mastermind to you?
I've read about a lot of different gambling/fixing schemes the FBI has uncovered but none of them involved a coach telling his team "you guys better play well enough to keep it within the number, but if we have to play stupid at the end to do so, we will."