GUWAHATI: In a bizarre incident, a son in-law raped his mother in-law in the city on Friday. Police sources informed that the incident took place at the Motghoria area. After the incident, the victim filed an FIR (First Information Report) at the 'All Women Police Station' in Pan Bazar here that very day. The police immediately registered a case (158/21 u/s 376 IPC). On Saturday, police arrested the culprit — identified as Bhupen Deka (30 years) – from his relative's house in Bhangagarh.