BHOPAL: A man killed his sister-in-law by setting her on fire in Madhya Pradesh's Ratlam district. The deceased has been identified as Nirmala, wife of Prakash who committed suicide six months ago. After her husband's suicide, Nirmala's in-laws abused her mentally and physically. Prakash's elder brother Suresh committed the brutal crime. He killed Nirmala accusing her of pushing his brother to commit suicide.