My ex jokes with his friends about killing me. Yet I still miss him.

My ex dumped me out of nowhere, just after we had amazing vacations together (that I mostly paid for working extra hours but that's not the subject) I did not understand because I felt he was loving me. I recently learned that after our breakup, he joke several times with his friends about destroying my réputation but worse than this, what to do to make my body disappear. I know I have dodged a big bullet but I still miss him, and I have this urge to reach out to him and make himself accountable about what he is telling to other people.