How exactly do I send a letter to a person in a Juvenile Detention Center when I am not sure exactly what one?

she is in I believe its Barrion center in Michigan but she got taken away for I am not sure what some sort of probation violation I think she was in court and this is a person who I really care about and want to let them know I am still here for them, I was trying to encourage her to get out of an abuse situation in her home and I believe her parents in revenge did something but I don't know what they wont give me details, and she is unable to contact me since I have a cellphone unlimited but it cannot recieve collect calls, and she is not sure of my exact address (I don't think she can remember with all thats going on) I am in Ann Arbor about an hour and a half away from here, help I really need to get in contact with this person the police here and in the area she was supposedly taken to refuse to give me any information