... did Michael have to be killed?
I thought early on in the movie, Jimmy's main henchman had said something about their not needing Michael anymore now that they had the machine, or something. Yet they keep going after him. I'm afraid that's kind of a key concept that, short of watching the movie again, please forgive me, I didn't quite catch.
The point wasn't to kill Michael per se, the point was to frame him for the murder of the only other scientist that knew about the machine (I noticed they made him visually unpleasant without personality, so the audience wouldn't care about him - they also lit him poorly! Think about someone charismatic, funny and with a great, fun personality.. the audience would spend half the movie mourning his death instead of focusing on the story, but it still smells of manipulation).
This would mean they have both people permanently out of the way, so they could do anything they wanted freely. The memory wipe means that even if the protagonist some day got free from prison, he wouldn't remember what happened, so wouldn't be a threat.
Though, why can't they let him just be, like the original plan was, is a mystery to me. Surely the memory wipe would've been enough, and they wouldn't have had to involve the FBI or anything. I guess the movie would've been very different, then.
Which is not a bad thing, considering what the movie is now.