Russian investigators want to assist their U.S. counterparts in probing the death of a 3-year-old boy adopted from Russia.
Russia's Investigative Committee vowed on February 19 that "all the necessary measures" would be taken to ensure those responsible "receive the most severe punishment."
The statement comes a day after Russian officials claimed the boy, identified as Max Shatto in the United States and as Maksim Kuzmin in Russia, was killed by his adoptive mother in Texas on January 21.
Russia's children's ombudsman, Pavel Astakhov, said the woman had beaten the boy and fed him powerful drugs.
A Texas Child Protective Services spokesman said the authorities had not yet determined whether the allegations of abuse and neglect were true.
Texas authorities said they were waiting for autopsy results.
The boy's father has declined to comment.
The U.S. Embassy in Moscow on February 19 decried the death as "a tragedy," but said it would be "irresponsible" to "assign guilt" before the completion of the investigation.
In December, Russia passed a controversial law banning adoptions of Russian children by U.S. citizens.
Based on reporting by AP, CNN, and Nationalpost.com