2. Keep evidences (notes, email etc)
3. Do not handle by your self. You are not qualified to handle this person.
4. Contact a lawyer right way (you will have a free consultation)
If your company is a big company in US, this person will be fired right way in US. If not, get a lawyer to sue this company. If you do not do it, you put your life at the huge risk. Your job is not worth your life.
If it is small company (100 less), considering resign from this job right way.