MOSCOW (BLOOMBERG) - A Russian court sentenced a historian of Stalin-era repressions to 3½ years for sexually assaulting his adopted daughter in a case that critics say was fabricated to punish him for his work.

Yuri Dmitriev may be released as early as Sept 12, state news service RIA Novosti reported, citing his lawyer, Mr Viktor Anufriev. Dmitriev, 64, was cleared of similar charges in 2018 and denies the accusations. Prosecutors had sought 15 years.

Human rights organisations claim he is being targeted for his work uncovering mass graves in the north-western region of Karelia that contain thousands of bodies dating back to Soviet dictator Josef Stalin's Great Terror. The European Union has labelled the charges against Dmitriev dubious.

"With political repression once again becoming routine in our country and as the truth about the past does not fit into the statist concept of history, it's natural that the authorities are hostile to activities to preserve the memory of past state political terror," the human rights group Memorial said this month. Dmitriev serves as the organisation's regional head in Karelia.

Russian history has become increasingly politicised and nationalistic in recent years under President Vladimir Putin. The state is named the defender of "historical truth" in a series of constitutional amendments approved in a referendum this month that also clear a path for Putin to remain in power until 2036.

The Kremlin says it was not involved in Dmitriev's case.

Dmitriev was initially arrested in 2016 on charges of child pornography involving his adopted daughter. He was acquitted in 2018, but later that year prosecutors opened a case against him over sexual assault.

"The state's strength is in its people," Dmitriev said in his closing statement earlier this month. "My path is to bring back from the abyss those people who perished at the hands of our state, unjustly accused, shot, buried in the woods like homeless animals."