Can an employer report harassing behavior by a disgruntled employee to police

I am an employer, On a commercial fishing boat. We make payroll by commision, We take the gross of the trip, expenses come off the top, The company that owns the boat gets half and the captain and crew splits the rest. Heres situation: After a trip a crewman (out on his first trip) Decides he was not paid enough. He was told that the profits on the trip could be anywhere from zero on up. But he acctually made a decent wage, As far as myself or others in the biz are concerned. But he feels he was ripped off. At the end of the trip he was paid, shown the profit-expense sheets and took his paycheck with a smile on his face and left the boat. A week later he runs out of money, so he calls up making threats and wants more money. He has messed with postings on Craigs list for advertisment for new employees, sent harassment advertising, harassed us in every way he can and is now threatening to take us to court for damages. Heres my question, Employers are the most open target of disgrunteled employees, what in this situation are my liabilites?if any and if I go to court over this what should I do?