How should one proceed to press charges for extortion and, possibly, get a restraining order?

A friend of mine is currently being harassed, threatened, and financially extorted by another employee in her company (different dept.). He is exhibiting classic abuser behavior by preying on her emotional weaknesses, making her believe he wants a relationship with her, but has extorted over $13000 from her. He has had people following her (at work and elsewhere) to keep tabs on her, threatened to make statements that could cost her job, threatened to enter into similar relationships with her friends, forces her to take out loans and sign her paycheck over to him, etc. What recourses does she have? She truly fears for her safety and well-being as he has threatened her with harm (both from himself and his people). He also has created a hostile work environment for her and other staff members.