The sheriffs department received a petition to modify custody a month ago. It was supposed to be served to my ex, but they can not locate her. My daughter is living with my ex's parents and they received their papers. They do not have custody or guardianship of my daughter.

What means have you used to locate her? Private investigator, something else? When the parents go to Court and are sworn in, ask them.

In my area the Sheriff will serve at the address provided. They do NOT search out a more current address. That is something you need to do.

I am confused about the circumstances. If DNA proves you are the father (or you were/are married to the mother) why can't you simply go and get the child? The grandparents cannot get custody or guardianship under those circumstances without your consent; therefore, I am assuming there was no DNA done or you were not married - ?

In the best interest of my daughter, I was advised by my attorney to not just go get her. She is in 1st grade in another town. If I go take her from the grandparents move her to my town and enroll her in school, her mother has the right to simply come take her from me until this is settled. If she drops my daughter back off with the grandparents, we will just be starting over again. The mother's address is the same as her parents, but she isn't staying there. The parents legally evicted her. She is mooching off friends and living off child support. She has no job, drivers license, or vehicle so it has been difficult to track her down. She hasn't even shown up to a single tball practice or game. I was hoping she would at least show up to that to be followed.