The vandals removed a marble cross from Taisiya Solzhenitsyna's grave earlier this week in the town of Georgiyevsk, in Stavropol Krai.
Solzhenitsyn's mother died in January 1944. Solzhenitsyn, who won the Nobel Prize in literature in 1970, returned to Russia in 1994 after two decades in exile.
(Interfax, AP)