rr22, I bet you're right about this being a pattern of behavior for him. This can't be the first time he's done something like this to a woman or even a co-worker. I shudder to think that he would do this to a student, but I can honestly say that I don't know who he really is.
I've told my boss, and he was really disturbed by it. He fully supports my wanting to no longer do trainings with this man. My assistant has been especially protective. When this man comes near, she never leaves my side, or she gets almost between this man and me. I just worry about running into him when I'm by myself at the copier or in a hallway.
I like the home security system idea. I'll start checking into that this weekend when I'll have time to do some research. Boxer dog is a pretty good deterrent to strangers (he's a big one), but he's not scary to people who know him!