Where: Russia

When: 2001 - 2006

Known as the "Chessboard killer" because he aimed to murder one person for all 64 squares on the gameboard. He is charged with 49 killings but evidence found at his flat suggests that he could've murdered as many as 62 people.

Many of the victims were homeless men. It is alleged that Pichushkin killed his victims by either smashing their skulls with a hammer or throwing them into sewage pits. He has been evaluated by psychiatric experts at Russia's leading institute, who have ruled him to be sane.

Pichuskin's deadly version of chess may be shocking but his murder spree puts him someway behind the world's worst serial killers.