So, here's the scenario. There's a serial killer, a spy, a witch, and a bus driver. Everyone knows who everyone else is. How does the SK and Witch Win? I guess, the key would be to figure out if the witch controls the Bus Driver, how is the Bus Driver affected?

My hypothesis is that the witch will change only one of the Bus Driver's targets. Any insight onto how this mechanic works?
(I remember that there used to be a post on DR's explanation on a whole bunch of game mechanics, but I'm unable to find it).