Tolokonnikova's disappearance can be traced back to when the 23-year-old musician was being transferred from a prison colony in Mordovia. "There's no proof she's alive, we don't know the state of her health," Tolokonnikova's father told Buzzfeed. "Is she sick? Has she been beaten?"

Tolokonnikova made headlines in September of this year when she went on a hunger strike to protest the conditions of the Mordovia prison, where she stated women were treated like slaves, forced to work through illness in deplorable conditions (she outlined the situation in an open letter, with an English translation printed in The Guardian).

She ended the strike when her health deteriorated to the point of falling ill and being taken to the prison hospital. According to Tolokonnikova's father, sources tell him that his daughter was last seen Oct. 24 on a train in the city of Chelyabinsk, where she was kept overnight after being transferred from the Mordovia prison.

"We think they moved her to a big city to hide her," her father explained, as Tolokonnikova's husband, Petya Verzilov, and a crew of supporters regularly demonstrated outside of the prison . "It seems they got sick of these protests."