Tomas, born in Ukraine, was arrested for stealing a cellphone -- a charge Tomas denies.
Following a medical examination of his teeth and genitals, prison doctors concluded that the boy was between 16 to 17 years old, allowing the court to judge him as an adult and put him behind bars.
However, Tomas' relatives say he was only 12 years old at the time of his arrest, a claim supported by his Ukrainian documentation, which was checked when he crossed the Russian border.
According to Article 20 of the Criminal Code, the age of criminal responsibility in Russia is 16.
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