Miller believes the body found Saturday in Shoreacres, Texas, is Abigail English, 15.
Miller says Abigail's family wants to cremate her, but Miller is asking the state of California to grant him custody of Abigail so he can bury her next to his daughter, Laura, who was kidnapped and killed.
"I'm in the process of filing for custody of little Abby so she can have that proper funeral, she can have that little headstone," said Miller.
The body has not been formally identified and no cause of death has been determined.
The remains were found in a wooded area off Baywood St., not far from where English had been living with her grandmother. She was last seen walking a dog March 22. The dog returned home, but Abigail never did. On Saturday, searchers initially found the dog's collar and leash. The remains were found not far away.
"This little child never had a chance in life. She was in foster care for 13 years; all she wanted was a family. November 2. she comes here to a family, and it really didn't work out," Miller said.
A La Porte school counselor reportedly contacted Equusearch about Abigail within the last few days. She was not immediately reported missing and was initially thought to be a runaway.
"When we have a throwaway child that never had a chance in life who wanted this family and ends up this way, something went wrong. Something went wrong and we'll let detectives figure out what that is," Miller said.
The wooded area became more overgrown with recent rain, which may have concealed the remains for more than a month. The Harris County Sheriff's Office has taken over the investigation and the medical examiner will have to identify the remains.
RELATED: Body found believed to be that of Abigail English