Mighty the people who told you to document, and get the evidence are sadly, spot on. Please do not ignore them. You need to protect yourself against a couple of unstable people. Otherwise it is 'he said' 'she said'.
The other point is that you are very very much in their minds. This would not have happened if she felt secure, and your xh felt guiltless. They would have thought it was unfortunate, and done nothing more. Look at behaviours. They do not lie. They over-reacted big time. Why???
I am not suggesting you necessarily get a restraining order, but I would document, get the facts, (like the security tape) Get it straight with the police, and keep your information close. I hope you don't need it, but if anything else happens you may.
In my experience they think about and obsess about us The happier we are, the more we cut them out of ourlives, the less they like it. They are messed up and they not only want, but need us to be part of their drama.
Jerry Springer does not make these people up. I wish he did!