Shortly after his release, he attempted to rape a young girl at knifepoint in Kemerovo, but the victim survived and Martynov was placed on a wanted list by police.

In June 2007, Martynov murdered a woman and dismembered her body in Glazov, Udmurtia, and the following month he raped an 8-year-old girl in Vyazovka, a village in Nizhny Novgorod Oblast.

In August 2010, Martynov raped and killed a 70-year-old woman in Bashkortostan, where he left a note stating that he is not afraid of the police and would be in Chelyabinsk at 12:00.

According to prosecutors, Martynov is believed to have committed violent crimes across at least 10 oblasts in western and central Russia since his release from prison until his arrest, killing seven women and one man, and assaulting numerous others.

Prosecutors said Martynov acted "daringly and cynically", leaving letters at crime scenes and making no effort to conceal evidence.