The 7-year-old boy, Artyom Savelyev, was put on a plane with a note saying his adoptive mother no longer wanted to parent him because he was violent and had severe psychological problems. While her actions were condemned by Russia's president and U.S. diplomats, the sheriff investigating the case said it's not clear if anyone can be charged.
"You know, you look at it and it's hard to say exactly if a law has been broken here," Bedford County Sheriff Randall Boyce said. "This is extremely unusual. I don't think anyone has seen something like this before."
Russia threatened to suspend all child adoptions by U.S. families over the treatment of the boy, who was called Justin Hansen by the Tennessee family.
The boy's adoptive grandmother, Nancy Hansen of Shelbyville, said the boy was violent and angry with her daughter. She said she flew with the boy to Washington and then put him on a plane to Moscow.
"He drew a picture of our house burning down, and he'll tell anybody that he's going to burn our house down with us in it," she told The Associated Press in a telephone interview. "It got to be where you feared for your safety. It was terrible."
Authorities in Tennessee were investigating the adoptive mother, Torry Hansen, 33.
Bob Tuke, a Nashville attorney and member of the American Academy of Adoption Attorneys, said abandonment charges against the family could depend on whether the boy was a U.S. citizen.
It wasn't clear if the adoption had become final. A Tennessee health department spokeswoman said there was no birth certificate issued for the boy, a step that would indicate he had become a U.S. citizen.
The sheriff said Hansen initially agreed to be interviewed by authorities but then postponed it after talking to a lawyer.
Boyce said it would be difficult to substantiate claims by Russian officials that the mother mistreated the child.
"We're here, and the child is in Russia, so it's hard for us to know whether this child has been abused," Boyce said.
The boy arrived unaccompanied in Moscow on a United Airlines flight on Thursday from Washington. The Kremlin children's rights office said the adoptive mother wrote in her note she was returning him because of severe psychological problems.
"This child is mentally unstable. He is violent and has severe psychopathic issues," the letter said. "I was lied to and misled by the Russian Orphanage workers and director regarding his mental stability and other issues. ...
"After giving my best to this child, I am sorry to say that for the safety of my family, friends, and myself, I no longer wish to parent this child."
Russian Foreign Minister Sergey Lavrov called the family's actions "the last straw" in a string of U.S. adoptions gone wrong, including three in which Russian children had died in the U.S. The cases have prompted outrage in Russia, where foreign adoption failures are reported prominently.
Russian President Dmitry Medvedev strongly condemned the family's actions, telling ABC News that the boy "fell into a very bad family."
"It is a monstrous deed on the part of his adoptive parents, to take the kid and virtually throw him out with the airplane in the opposite direction and to say,
'I'm sorry I could not cope with it, take everything back' is not only immoral but also against the law," Medvedev said.
