I am 39 years old. I have a home, a have a teenage daughter graduating High School this month and I have a great career. In 2007 - I decided to find my biological father. I've always been told his name so I guess it was pretty easy for me. I did locate him, we did a DNA test and it came back 99.99994% - so obviously, he's my father. Since finding him, we've been in contact weekly sometimes 2 or 3 times a week. I am grateful for having been given this opportunity. He does have 3 other children with his ex-wife. A daughter who is 1 1/2 years younger than me, a son that is 30 and another son that is 19. Both of the boys have not had any problems with me finding my biological father, but for some reason, the daughter is jealous and completely devastated. She has refused to speak to our father because of this. Recently, my father was in my home town because he was going to court on his ex-wife and I offered to go with him since his other children didn't want to get in the middle of a mother/father dispute (totally understandable). My fathers wife could not be here and she asked me to go as well. After finding out that all his kids were upset that I was going - I elected not to go. From that point on - his daughter has sent a certified 3-page letter to my fathers wife telling her all kinds of things about me and my family that are horrible and completely untrue. I'm wondering if I can finally put a stop to all this crap by suing her for slander or defamation of character? Does anyone know what legal steps I can take at this point? She's even gone as far as calling my home and making a threat, "Your day is coming "... she didn't care who was on the phone and my 18 year old daughter actually got the call. What can I do right now?

You cannot sue for slander as you do not appear to have anything to sue for.

She can send a letter to whomever she wants and as long as there is nothing illegal in the letter (such as a threat) , you have little grounds to sue unless you can PROVE damages and quantify the value of the damage done.

As for her calling the house, if it continues or she makes legitimate threats (your day is coming is not a threat... it's a bad movie line), call the police and have her cited for harassment.

Honestly, as long as she doesn't break the law, there isn't much you can do, particularly since she is "family".