Wow. That's some nasty shit there (the trashed desk, but mostly the multiply-cut cables - that's just being a dick). But like you said: a small price to pay to be rid of him.
I was thinking about it, and wondering if in his paranoia (colloquial def'n, not clinical one), he wasn't so much spying on you, but trying to keep track if someone else was spying on him... in other words: not so much that he wanted to see what you were doing, but to be able to see instantly if someone was looking at him. With him not liking to be 'tracked', that seems a possibility (if only of intellectual, not practical, interest).