The Karelia Supreme Court overturned Gulag historian Yuri Dmitriev’s previous sentence and on Tuesday sentenced him to 13 years in prison. 

Dmitriev is known for finding the memorial at Sandarmokh, which is a mass grave site, his work with International Memorial, and documenting the horrors of the Stalin regime.

In July the Karelia Supreme Court convicted Dmitriev of sexually abusing his adopted daughter and sentenced him to three years and six months in prison. However, since Dmitriev served time in pre-trial detention, he was due to be freed sometime soon. The court then abruptly added 13 years to his sentence.

Many have criticized the decision and claim it is politically motivated. On Monday 250 cultural figures sent a letter to the Karelia Supreme Court and requested that Dmitriev’s case be transferred to another region. The signatories include “rights defenders, academics, politicians, writers, journalists, actors, and film directors.”

The EU condemned the prolonged sentence and stated that “Mr. Dmitriev’s prosecution was triggered by his human rights work and his research on political repression in the Soviet period.” In addition, the EU believes Dmitriev should be released “immediately and unconditionally.”

Artem Cherkasov, one of Dmitriev’s lawyers, said they will appeal the decision.