Several years ago (I'll try and find links, but this was back when physical newspapers were still common), some undercover cops did escalate a situation, and the man they were after drew a gun on them (he didn't know they were cops). But the only thing they actually had on the guy was that he drew his gun on them (he didn't fire it). The police tried to have him charged, but the judge ruled given the circumstances that they were undercover and because there was sufficient evidence to show the undercover cops were the ones who escalated the situation, the man was found not-guilty (I think, if I remember correctly, the man in question used self-defense as his court defense, and the judge sided with it). These police officers, because the man made them "fear for their lives," pushed to have him retried, for the same crime; it never happened, because of course that would be double-jeopardy.