Harment from Father in Law?

A little bit of background information. When my father in law got divorced from my mother in law, the swat team had to be called out because he held his entire family hostage with a gun threatening to kill them all. Before that (and after) he had an extremely bad streak for drinking and becoming angry which lead him to abuse his son/daughter/wife. He now blames all women for his ex-wifes problems, saying that he does not like, and has never liked me. He's told my husband several times that I'm a , that i'm probably a stripper on the side, and several other things. I'm not a stripper, have never been a stripper and am not promiscuous. I am now 6 months pregnant, and my husband is deployed to Iraq. My husband doesn't even like talking to his father. He's been gone for almost 3 months. My father in law calls me every couple days, here recently I have not been answering/returning his phone calls. Every time he calls he wants to talk about my husband dying which stresses me out, or he yells and cusses and threatens me. Now he is leaving me voice mails yelling and cussing at me. Is there anything legal that I can do? I've asked him not to leave vulgar messages on my phone, not to talk to me like that. I don't want him to get into any serious trouble, but I also will not stand to be talked to like that... Thanks.