Need a lawyer to begin a lawsuit

I have a neighbor that keeps sending me anonomous letters each year saying nothing but nasty and harassing things about my family ,they call police and code enforcement to harass me and installed a camera overlooking my backyard to harass us. Last year they told the neighbors grandmother not to let my son near her grand daughter as he might hurt her and that he sexually abused her daughter, which never happened! This last letter she called my son a pediphile, made statements about calling CPS for my innocent 7yr old daughter exposing herself in my backyard and threatening to go to my wifes job to make problems for her with her employer , etc. etc. I've had enough and want to sue them so where do I begin? Thank you