Russia on Tuesday raised serious concerns about a US decision not to prosecute the adoptive parents of a Russian boy whose death has sparked a diplomatic row between the two countries.
Russian officials claim toddler Max Shatto -- born Maxim Kuzmin -- was tortured and murdered in January by his adoptive US mother, whipping up a storm of controversy less than two months after Moscow banned US adoptions.
On Monday, a Texas official said there was no "evidence to support holding anybody criminally responsible" for the death of the three-year-old, adopted in Texas by Alan and Laura Shatto.
"The Texas authorities' decision not to press charges against the Shatto couple over the tragic death of Maxim Kuzmin raises serious questions," said Konstantin Dolgov, the Russian foreign ministry's special representative for human rights.
The US Ambassador to Russia, Michael McFaul, tried to calm the storm on Tuesday, saying at a public question-and-answer session in Saint Petersburg that he trusted the US decision and insisting that the case should not be viewed as political.
"For us, this is not a case of confrontation or a Cold War between the two countries. Who could support violence against children? It is horrible. We want to work together on this," McFaul said in comments in Russian.
"I trust the Texan sheriff," McFaul said, referring to the local law enforcement official responsible for the case. He added that he felt the US police "worked in an efficient and friendly way with the Russian side."
The boy's body was heavily bruised when he died at a hospital near the west Texas town of Gardendale, but US doctors determined earlier this month that his injuries were self-inflicted.
The coroner also noted that he had a mental disorder that caused him to harm himself.
"The child has died but his adoptive parents are not guilty. Moreover, there is an attempt to convince us that it was the boy who inflicted his fatal injuries upon himself," Dolgov said in a statement.
He also said that the latest decision showed that US law enforcement agencies were too lenient towards US adoptive parents, adding that Russian authorities would conduct their own investigation.
"We are reiterating our request to provide the Russian side without delay with all the necessary documents related to the circumstances of Maxim Kuzmin's death including autopsy results," Dolgov said.
The Shattos are also raising the child's younger brother, known under his Russian name Kirill Kuzmin. Russian officials are now trying to bring the boy back home.
Dolgov requested that the United States give Russian officials unlimited access to the two-year-old "to determine the real conditions in which he's now living."
Late last year, Russia banned all adoptions by American parents as a reprisal for US legislation targeting Russian officials deemed to have committed rights abuses.
The Kremlin's child rights commissioner Pavel Astakhov also said he regretted the Texas authorities' decision, accusing them of refusing to conduct a "thorough investigation" into the boy's death.
"Terminating prosecution of the Shatto adoptive parents by the Texas attorney means rejecting all earlier suspicions," he said on Twitter.
In early March, US authorities ruled the boy's death to be accidental and cleared his US parents of homicide.
Russian officials had hoped the Shatto couple would face negligence charges for leaving the boy alone in the yard of their home.
The bill banning adoptions was named after Dima Yakovlev, a Russian toddler who died of heat stroke in 2008 after his adoptive American father forgot him in a car.
The father was acquitted of involuntary manslaughter.