I am familiar with this form of passive aggressiveness and it is, in my opinion, just as threatening as words. Sometimes, words are less threatening as they are a quick release of anger, whereas a "meaningful display of action" may be much more intense and scary.
However - prove it, right? Perhaps he admitted it, or did so to a point. Those who may-say the police may be missing an important mental health and/or domestic violence aspect to the story.
That is what is often awful in stories like this. Signs may be there, but the law cannot do anything without public outcry. Unfortunately, it wouldn't be as bad if more people had trust and faith in law enforcement - if corruption was not so rampant it would be so.