Well, loss of his legally obtained firearms, anyway. Legal action by the this guy's declared target is useful only if he is jailed immediately after the complaint is made and there is ironclad surety that he will go to prison for many years without any bail time.
I respectfully disagree.
Bullies respond best to an unexpected punch in the head, proverbial as well as physical. Legal action would likely disarm him, and even a RO would force him to maintain a distance. Keep in mind that the last thing that this guy wants is, as a cop, to be thrown into jail. Moreover, you’re building a paper trail that backs up and is supported by the reasons for the firing. If multiple officers were threatened, multiple officers should respond with the same legal recourse.
If that isn’t suggestive enough, then it’s time to meet the next personal threat with whatever level of brutal, overwhelming force is appropriate to the confrontation.