Suspect X is a 2008 Japanese mystery-thriller film based on the novel, The Devotion of Suspect X, directed by Hiroshi Nishitani. The film was a continuation of the popular Japanese serial drama Galileo and included the same cast. It topped Japan's box office for four consecutive weeks and was the third-highest-grossing Japanese movie in 2008. The soundtrack was released on October 1, 2008. Suspect X was the first of several film adaptations of The Devotion of Suspect X, followed by Perfect Number (2012) from South Korea and Kolaigaran (2019) and Jaane Jaan (2023) from India.