Can someone tell me ho i can find my dad if all i know is his last name? i have clues?

ok my mom told me i have a real father that the man im living with is not my real one. i have been looking on many many sites trying to find him. i know his last name is palmer. he spent most of his life in Fort Wayne Ohio he may of been born there idk. anyways i know that he had 2 children in Reno Navada i dont know there names or the womans name but i know he ually abused my 2 sisters there i looked on renos offenders list but i didnt find anyone with last name palmer. im Fort Wayne however i know that there was a court case with him and my mother Catherine Palmer (at the time her name) about him tempting to kill her and sell me as a baby to mexico for drug money. he may have a huge police record involving s, murders, drug use, pedophile ones a lot of things. my mom refuses to tell me his first name and she has no living brothers or sisters both parents dead so i have no one to ask whos related to her. i have no intentions of meeting him for saftly of my own life i just want to know his name or maybe even a picture. i have been searching so long but its hard with only a last name can anyone help plz im desperate