Evgenia Kara-Murza wrote on social media platform X that her husband, who suffers from a nerve disorder after surviving two poison attacks, had been in solitary confinement during the four months he had spent in the harsh-regime IK-6 colony in Omsk.
Convicted prisoners can disappear for long periods while being transferred by rail and prison car between far-flung points of Russia's penal system. In December, the family and lawyers of opposition leader lost contact with him for nearly three weeks while he was being moved to a penal colony in the Arctic.
The Russian prison service did not immediately respond to a request for comment on Kara-Murza's whereabouts.
The dissident was jailed for 25 years last April for treason and spreading "false information" about Russia's war in Ukraine. He denied the charges and compared the proceedings to Stalinist show trials of the 1930s.
Kara-Murza, 42, has a condition called polyneuropathy that
takes away the sensation in his limbs unless controlled by
medicines and exercise. His wife has voiced fears for his life in jail.
Poisoning episodes in 2015 and 2017 sent Kara-Murza into a coma both times. Navalny too survived an attempt to poison him with a nerve agent in 2020.
Kara-Murza, who holds Russian and British passports, is one of a small number of prominent opposition figures who stayed in Russia and continued to speak out against President Vladimir Putin after his February 2022 invasion of Ukraine.
(Reporting by Reuters; Writing by John Davison; Editing by Mark Trevelyan)
