Married couple Igor and Kristina Dvornikov have been charged in the killing of Vika Teplyakova, whose body was found dumped in a forest after they offered her a ride.
In her first interview, Vika's grief-stricken mum Ulyana said her only hope is the suspects suffer the "most terrible and painful" fate, are never released from custody and wind up in the depths of hell after they take their final breaths.
Vika ran away from home following a row and was walking alone next to a road when she was picked up by the Dvornikovs, who spotted her as they drove by, according to police.
Vika, who was missing for three days before her body was found, would have celebrated her ninth birthday on Sunday.
Instead of celebrating her birthday, her devastated family will bury her on Monday.
Mum Ulyana said she is struggling to cope with her grief and she is taking sedatives because she is so overwhelmed by the pain of losing her daughter in such a brutal way.
The mum, from Novoaleksandrovsk, Russia, told Life: "Of course, I would like the most severe punishment so that these people are never released.
"All I can wish for is the most terrible and painful punishment for these people. I do not hide it.
"I hope the punishment is as strict as possible and I hope that soon these people will end up in hell."
Ulyana said her daughter was well-behaved and friendly, and loved to play football, sing and record videos.
