PRAYAGRAJ, June 28 -- Police have filed a case against four people in the case of the death of a shopkeeper, his mother and wife, in the Sagara Sundarpur market area, under the Leelapur police station of Pratapgarh. It is alleged that all three were killed by poisoning. Cosmetics shop owner Ankit Patwa, his mother Asha and wife Riya, were found dead on the same bed on Thursday morning. A panel of doctors conducted the post-mortem examination of the bodies amid videography but the cause of death could not be ascertained. In such a situation, the viscera was kept safe for investigation. On Friday, Ankit's father-in-law, Deep Kumar Patwa, a resident of Gaura Pure Badal in Fatanpur, filed a case against four people for poisoning Ankit. According to Deep Kumar, Ankit had a house dispute with Bhola Patwa of Gadwara Bazaar, his son Satyam Patwa, Raju Patwa of Gauradand and Dharmendra Patwa. These people had threatened him several times. Deep Kumar believed that these people fed Ankit, his mother and wife poisonous substances which led to their death. After the three bodies were found, police seized the DVR of CCTV installed in his house. Due to the door of the house being open, people were suspecting someone must have entered the house. When the police saw the CCTV footage, no outsider had entered the house at night. The tantrik who had talked to Ankit on his mobile phone for more than 15 minutes at 11 pm on the night of the incident, was questioned by the police on Friday. The tantrik told the police that Ankit had called at 11 pm and said that he was feeling nauseous. He said some mantras on the mobile phone itself. The tantrik had also talked to his wife and repeated the same on the phone....