The State Department confirmed Tuesday that it has informed Guatemala's  government that it can't help return Anyeli Hernandez Rodriguez because the U.S.  and Guatemala had not signed the Hague Abduction Convention at the time of the  alleged kidnapping in 2006.

"We're obviously deeply concerned about allegations regarding stolen children  and intercountry adoptions wherever these cases come up," State Department  spokeswoman Victoria Nuland said in a statement. "We consider the appropriate  venue in the United States for pursuing this case is in the state courts.  They're the competent organ for holding a full hearing on the merits and the  best interests of the child."

A human-rights group that has pursued the case in Guatemala's courts on  behalf of the child's biological mother, Loyda Rodriguez, said the next step  will be to find a U.S. law firm to file a civil suit charging immigration  fraud.

The group, the Survivor Foundation, doesn't allege that the adoptive couple  knew anything about the girl being kidnapped. It argues only that the adoption  in 2008 wasn't valid because of the abduction and the girl should be returned to  her biological mother.