The incident occurred on the occasion of Bhai Duj on FridayA woman and her son were arrested on Saturday for attempting to murder their relative in outer Delhi. A senior police official said that the incident took place in Aman Vihar. Representative picThe accused were identified as Hari Chand and his mother Rukmini. They live in C-1 block of Hari Nagar area. Sonu, Hari Chand's brother-in-law, had come to meet his sister on the evening of Bhai Duj. Hari Chand had an argument with his wife. Things got heated up. Sonu tried to intervene and was shouted at by Hari Chand. Meanwhile, Rukmini also joined them. She provoked Hari Chand to kill Sonu. In a fit of rage Hari Chand brought out a sharp-edged weapon from the kitchen. Rukmini caught hold of Sonu while Hari Chand stabbed him, said a police official.Sonu fell on the floor in a pool of blood. Hari Chand's wife informed the police that her brother was stabbed by her husband. A police team visited the crime scene and rushed Sonu to Sanjay Gandhi Memorial hospital where he is still undergoing treatment and his condition is stated to be critical by doctors.An FIR under section 307 (attempt to murder) has been lodged at Aman Vihar police station. Rukmini and Hari Chand were arrested and sent to jail by the police, added the official.