The Oxford Murders by Guillermo Martinez

A paperback sensation in Argentina, Spain, and the United Kingdom, The Oxford Murders has been hailed as "a remarkable feat" (Time Out London) and its author as "one of Argentina's most distinctive voices" (The Times Literary Supplement). It begins on a summer day in Oxford, when a young Argentine graduate student finds his landlady-an elderly woman who helped crack the Enigma Code during World War II -murdered in cold blood. Meanwhile, a renowned Oxford logician receives an anonymous note bearing a circle and the words "the first of a series." As the murders begin to pile up and more symbols are revealed, it is up to this unlikely pair to decipher the pattern before the killer strikes again.