The adoptive parents of a three-year-old Russian boy who died at their Texas home will not be charged with a crime, prosecutors say, in a case that has become a flashpoint on the issue of Americans adopting Russian children.

Russian authorities and state-run media have blamed the parents for the boy's death and used the case as justification for a recently enacted ban on all US adoptions of Russian children.

Bobby Bland, the district attorney in Texas' Ector County, said on Monday that his office would not charge Alan and Laura Shatto in the January 21 death of Max Alan Shatto, who was born Maxim Kuzmin.

"The grand jury determined there was insufficient evidence to charge them with anything," Bland said in a news conference.

"This death was the result of a tragic accident occurring most likely on playground equipment," Bland said. "When a child dies so young and tragically, it is natural to want to hold someone accountable. However, in this case, there is no evidence to support holding anybody criminally responsible."

Laura Shatto told authorities that she found Max unresponsive outside their Gardendale, Texas, home while he was playing with his younger brother, County Sheriff Mark Donaldson has said.

The boy was pronounced dead in hospital a short time later. Preliminary autopsy results indicated Shatto had bruises on several parts of his body, though four doctors reviewing the final autopsy result ruled his death to be accidental.

Bland, the top prosecutor in Ector County, about 560km west of Dallas, previously said that the bruises on Max's body appeared to be self-inflicted, and that no drugs were found in the boy's system.

Russian investigation

Russia's Investigative Committee has said it has opened its own investigation. It is unclear whether the committee could charge the family or force their prosecution.

The Russian government passed a ban on adoptions in December in retaliation for a new US law targeting alleged Russian human-rights violators.

The ban also reflects lingering resentment over the perceived mistreatment of some of the 60,000 children Americans have adopted over the last two decades. At least 20 of those children have died, and reports of abuse have garnered attention in Russia.

Konstantin Dolgov, a Russian foreign ministry official, has called Max's death "yet another case of inhuman treatment of a Russian child adopted by American parents".

Texas Child Protective Services spokesman Patrick Crimmins said the agency was investigating allegations that Max was subject to physical abuse and neglect but had not determined whether those allegations were true.

The agency that processed the Shattos' adoption, the Gladney Center for Adoption in Fort Worth, was cleared in a separate state investigation to find out whether it followed prescribed guidelines.

The Shattos adopted Max and his biological half-brother, two-year-old Kristopher, from the same orphanage in western Russia. Since Max's death, Kristopher has remained with his adoptive parents.

Source: Agencies