Sattam Oru Iruttarai (transl. The Law is a Dark Room) is a 1981 Indian Tamil-language vigilante action film written and directed by S. A. Chandrasekhar, from a story by his wife Shoba. The film stars Vijayakanth, Poornima Devi and Vasumathi, with Sangili Murugan, Nithin and Chowdry in supporting roles. It revolves around a man who seeks to kill three men to avenge his father and elder sister, while his other sister, a police inspector, wants to thwart them the legal way.