Angry Russian officials are calling for a halt to all U.S. adoptions until the two countries can hammer out a new agreement that spells out the conditions and obligations for such adoptions.
Russian President Dmitry Medvedev called the boy's abrupt return "a monstrous deed." The Russian president told ABC News' George Stephanopoulos in an exclusive interview that he had a "special concern" about the recent treatment of Russian children adopted by Americans.
Torry Hansen of Shelbyville, Tenn., put 7-year-old Artyem Saviliev -- renamed Justin Artyem Hansen in the U.S. -- on a plane to Moscow's Domodedovo airport with a note in his pocket saying she was returning him, that the boy had severe psychological problems and that the orphanage had lied about his condition.
"I no longer wish to parent this child," the note read, calling the boy a liability.
"This child is mentally unstable." Hansen wrote to the Russian Ministry of Education. "He is violent and has severe psychopathic issues/behaviours. I was lied to and misled by the Russian Orphanage workers and director regarding his mental stability and other issues."
Adopted six months ago, the boy was traveling on an expired U.S. visa. He was taken to a hospital for a medical evaluation. Video footage showed Artyem looking bewildered as he is taken from the police station to the hospital by Russian social service workers.
"On every level putting a little kid on a plane and shipping them somewhere is horrific behavior. If you have a problem, you deal with the problem," said Adam Pertman, executive of the Evan B. Donaldson Adoption Institute. "It is certainly the equivalent of abandoning your child."
Bedford County Sheriff Randall Boyce told ABC News that he had tried to visit Hansen Thursday and again today, but was told by Hansen's lawyer "they said they will meet with us later, sometime next week they said."
"This is a touchy deal and I'm not sure if anything illegal has been done or not," Boyce said.
The sheriff said, "Our plan is to have the adoption agency check with the people in Moscow or whatever part of Russia they're in and check with this child and see if they see signs of abuse."
Boyce said he intended to move slowly and carefully in his investigation.
"We're breaking new ground here," he said. "There may be no crime at all when you really get down to it. Maybe some bad judgment in the way she turned this child back."
The Tennessee Department of Child Services also is looking into elements of the case.
"DCS looks into child abuse and neglect," said Rob Johnson, the department's director of communications. "By statute we look into cases alongside law enforcement. We look at it from a child welfare point of view.
"We have tried to visit the Hansen family today," Johnson added. "We are working alongside law enforcement on trying to interview them."
Of particular interest to DCS would be the safety of any children that may be in the Hansen home, Johnson said.
"We do not track international adoptions," Johnson said. "They are private adoptions."
Nancy Hansen, the boy's grandmother, told The Associated Press that she and the boy flew to Washington and she put the child on the plane with the note from her daughter.
She told the AP that the child began hitting, kicking and spitting and making threats in January.
"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," Hansen said. "It got to be where you feared for your safety. It was terrible."
Nancy Hansen said she and her daughter, a single mother, went to Russia together to adopt the boy, and she believes information about his behavioral problems was withheld from her daughter.
"The Russian orphanage officials completed lied to her because they wanted to get rid of him," Nancy Hansen said.
Artyem, who turns 8 next week, "was accompanied from his home in Tennessee to Washington by his American grandmother, who put him on a direct flight to Washington to Moscow," U.S. embassy officials told ABC News.
His grandmother reportedly told him he would be happier in Russia before handing him over as an unaccompanied minor for his flight to Moscow.
A friend and neighbor of Torry Hansen, who identified himself only as "Mr. Austin" said the Hansens were a nice family and the boy had been causing problems, including setting fires and trying to burn the house down.
A spokeswoman for United Airlines told ABCNews.com via e-mail that while she could not confirm Artyem's presence on the flight to Moscow, "all procedures for flying any unaccompanied minor who may have been on this flight were followed."
Those procedures include not allowing an unaccompanied minor to travel on a one-way ticket and making sure the child boards the plane with signed paperwork and a name, sometimes even a photo, of who will care for the child at the destination.
The family had paid a driver $200 to meet the boy at the airport and take him to the Ministry of Education. Once there, officials found his U.S. passport, adoption documentation and Hansen's letter in his backpack.
"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," it read. "As he is a Russian National, I am returning him to your guardianship and would like the adoption disannulled."
U.S. embassy officials were immediately contacted and they met Artyem at the children's hospital where he was being examined. The boy is physically fine according to Russian media reports, but Kremlin's Children Rights Commissioner Pavel Astakhov told reporters outside the hospital that he is traumatized by the ordeal.
Artyem cried when he was asked about his family in America, saying his mother used to pull his hair and his grandmother always shouted at him, Astakhov said.
Russian Foreign Minister Sergey Lavrov said today, according to The Associated Press, that "we have taken the decision ... to suggest a freeze on any adoptions to American families until Russia and the USA sign an international agreement."
While he understand's the knee-jerk reaction in Russia to protect their children, Pertman said banning all adoptions isn't the way to go.
"There are lessons to be learned from this," he said. "Ensuring that all the other kids that need loving homes don't get them is not the way to solve the problem."
Most adoptions from Russia end well, experts say. But a series of highly-publicized cases of parents who say their Russian children come with several mental and behavioral issues, some to the point of extreme violence, have cast a pall both on the country's orphanage system and the American parents who sign up to take on the children.
Virgnina mother Peggy Sue Hilt is serving 25 years in prison for the 2006 beating death of her 2-year-old, Russian-born daughter Nina. Hilt told ABC News' "20/20" that Nina was impossible to handle from the beginning, withdrawn and prone to banging her head against things.
Hilt began drinking heavily in secret and one day, finally lost her patience.
"Nina picked up a fork off the table and went towards [her sister] with it, and I saw red," Hilt said. "I grabbed her and I snapped. I hurt her. I didn't mean to hurt her. Then I kicked her with the side of my foot and told her to get up and then I put her up in her bed and struck her repeatedly."
Fifteeen cases of Russian children murdered by their parents have been recorded in the United States since the early 1990s, causing concern on the part of Russian and American officials.
While there is no behavior that can excuse child abuse, Pertman said orphans in Russia are often institutionalized and, as a general rule, institutionalized children suffer higher rates of attachment and behavioral disorders.
"You can not live in an institution for years and suffer no consequences," he said. The answer, he said, lays with foreign countries minimizing damaging environments for the children and U.S. adoption agencies doing a better job of vetting and education potential adoptive parents.
"Of course your heart breaks for this child," Pertman said of Artyem. "People should not get the impression that all Russian kids have these problems."
According to government statistics, the number of Russian children adopted to U.S. families has sharply declined in the last 10 years, down from a high of 5,862 in 2004 to 1,586 last year.
ABC News' Kari Pricher Scott Mayerowitz contributed to this story.