Rourkela: A 38-year-old man was arrested for allegedly killing his father and injuring his wife with a wooden plank over suspicion that they were having an illicit relationship, police said on Wednesday.The incident took place on Monday at Baxihating village under Lahunipada police station limits in Sundargarh district’s Bonai subdivision. The accused was identified as Ruben Soy. His father, Dayal Soy (60), succumbed to his injuries at a hospital in Rourkela, while his wife, Jasmina Lugun (30), is undergoing treatment.According to police, Ruben quarrelled with his father and wife over his suspicion that they were having an affair. Around 11 am on Monday, he allegedly returned home drunk and repeated the accusation. When both protested, he allegedly picked up a wooden plank and assaulted them. Neighbours rushed to the house after hearing their screams and took the injured duo to Lahunipada community health centre. They were shifted to Rourkela Govt Hospital and subsequently to a private hospital.Ruben allegedly fled after the attack. Police registered a murder case and launched a search before arresting him on Tuesday night. The plank used in the attack was seized, said Tapaswani Kiro, Lahunipada police sub-inspector.