The family of one of the jailed members of the Pussy Riot protest band have revealed they are unaware of her location after she was moved to a new prison 10 days ago.
The husband of Nadezhda Tolokonnikova told The Daily Beast he had not received any news about her and her current location was currently being kept secret.
Petr Verzilov, told the US news site that the last time he received information about his wife was over a week ago, and that a train had taken her through Ulyanovsk and Ufa to Chelyabinsk.
Her disappearance comes after she publicly claimed to have suffered extraordinary "slavery-like conditions" at Russia's feared Penal Colony No 14.
Nadezhda Tolokonnikova has disappeared
He immediately flew to Siberia to look for his wife. But in spite of all his efforts to find out where she was, officials preferred to keep Tolokonnikova’s location secret. The punk-turned-inmate is now feared missing.
“This is how the system makes a person disappear without a trace for weeks,” Verzilov said.
Her husband told Buzzfeed he believed the decision to move his wife came from the authorities in Moscow: "They want to cut her off from the outside world."
He said Ms Tolokonnikova was still weak after two hunger strikes, and accused the authorities of trying to punish her because of her protests.
She and another band member were jailed over a protest in a Moscow cathedral.
Another band member also added her concerns.
“After two hunger strikes she had in October she must be still weak and physically vulnerable—I am very worried about her,” said Pussy Riot member, Yekaterina Samutsevitch, to The Daily Beast.
They were sentenced to two years' imprisonment after performing a risqué protest song in February 2012. A third band member was released on appeal.
Pussy Riot's act was regarded as blasphemous by many Russians, but their prosecution has sparked an international outcry.
She was seen on 24 October by a fellow passenger as the train arrived in the city of Chelyabinsk, in the Ural mountains.
Ms Tolokonnikova has previously complained of suffering abuses by the prison staff in Mordovia.
Last month, she wrote an open letter published in The Guardian where she announced she would begin a hunger strike over the slave-like conditions, beatings, death threats, forced stripping of female inmates and banning of toilet breaks that occurred at the prison.
Mordovia, some 445km (275 miles) east of Moscow, has labour camps dating back to the notorious Gulag system set up by Soviet dictator Joseph Stalin.