Dennis Christensen was the first Jehovah’s Witness to be convicted in Russia this year after the country declared the group “extremist” in 2017. Christensen, whose conviction was condemned by critics as a crackdown on religious freedom, is serving a 6-year sentence in western Russia.

A Danish Jehovah’s Witness jailed in Russia on extremism charges has accused prison guards of “planting” a knife and then filming its discovery in his cell, the religious organization said.

The alleged planting and discovery of the knife in Christensen’s cell late in July “was used to pressure the believer,” the Jehovah’s Witnesses in Russia organization said on Thursday.

Wardens in the Kursk region prison colony are “trying unsuccessfully to keep Christensen from discussing the Bible with cellmates, although it’s not prohibited under colony rules,” the group said.

The Jehovah’s Witnesses in Russia also claimed that a regional human rights official had expressed bewilderment that “a sectarian from abroad had come to our Orthodox country.”

The religious group’s world headquarters in New York has estimated that 175,000 adherents reside in Russia, though hundreds may have fled the country since the court ruling that banned the group. Nearly 200 Jehovah’s Witnesses in Russia are facing criminal charges, the group has said.