When to report to police

Hello friends,
What do you suggest doing if my ex narc recently sent me a letter from a lawyer threatening to get a pfa against me, report me to my ethics board and call the police on me if I continue to communicate with him. I haven’t seen or talked to him in months. I’m not sure if I should make a police report to document this to protect myself if he makes up lies. Any ideas? I did have a lawyer answer his lawyer and say that I’m not contacting him and to not send letters like this. What do you think?