(CNN) -- Investigators haven't been "afforded an opportunity" to interview a Tennessee family that sent an adopted boy back to his native Russia alone, the county district attorney's office said Tuesday.
The office of Bedford County District Attorney Charles Crawford said authorities were seeking such an interview and another with the 7-year-old boy who, according to the family, had been exhibiting violent and psychotic behavior.
The child was put on a flight to Moscow and showed up unannounced Thursday at Russia's child protection ministry, and triggered an international investigation that threatens to end Russian adoptions by American families. Russia has suspended the license of the Washington-based agency that facilitated the Tennessee adoptions.
Julie Snyder, a spokeswoman for the World Association for Children and Parents in Renton, Washington, said that "in unusual situations like this, it is expected that authorities would suspend an agency until a full investigation can be completed."
The Bedford County sheriff's office and the Tennessee Bureau of Investigation are investigating the incident at Crawford's request. It said it was probing the "acts and omissions" of adoptive mother Torry Hansen and her mother, Nancy Hansen.
"Thus far, law enforcement has not been afforded an opportunity to speak with either of the Hansens," a statement from the district attorney's office said.
"An interview with both would be extremely helpful in our efforts to discover what events led to Torry Hansen's decision to attempt to nullify the adoption and why the Hansens sought to accomplish that goal in the manner they purportedly did."
A note found in the child's backpack said that Russian orphanage workers "lied to and misled" Torry Hansen about the boy, Artyem, who was renamed Justin Artyem when the family adopted him last year.
The district attorney's statement said investigators must also speak to the boy. "An effort is already under way to arrange that interview," it said, and offered no further details.
Crawford said earlier that officials have not determined whether the case constitutes child abandonment, and that if there was, it took place at the airport in Washington, where the boy boarded the plane.
The Tuesday statement said that any potential criminal charges the county may file must have been committed at least in part in Bedford County.
Jim Plowman, the attorney for Loudoun County, Virginia -- where Dulles Airport is located -- said in a written statement that he was not pursuing any charges. "It does not appear that Loudoun County is the most appropriate venue for prosecution, should any exist," he said in a written statement sent to CNN on Tuesday.
He said that the use of an airport in the county is "not, of itself, sufficient to convert the matter to a purely local case."
Plowman called the matter troubling and said his office was willing to assist in the investigation if asked.