Joker Special (2010)

Date Kazuyoshi (Sakai) is a detective on the Kanagawa prefectural police force. During the day, he is known as a "Buddha" for his gentle personality, pouring all of his energy into resolving each case. At night, however, he transforms into a cruel punisher as his gentleness gives way to his anger towards the criminals. The series poses questions about what justice and evil truly are.