Rakib Ali, the only son of the 48-year-old Rizia Bibi, had told his neighbours in Bishnuhati village on Sunday that his mother had suddenly gone missing, Jamalpur Police Station officer-in-charge Sanjib Ghosh said.
Rakib would often quarrel with his mother as she refused to concede to his demands for handing him the family farm land. A woman in the neighbourhood spotted a piece of cloth sticking out from under the septic tank cover this morning and alerted others in the neighbourhood.
They opened the tank and found Rizia Bibi's body wrapped in cloth in a sitting position and covered with hay to avoid detection.
The police was informed and the son during interrogation confessed he had hit his mother under ear at the heat of the moment on Sunday, Ghosh said. She had fallen down after the blow and he found she had died.
Following this he had hit the body in the septic tank to avoid being caught, Rakib told the police. The police later arrested him. A complaint was filed by a relative who also accused Rakib's wife, who had gone to her parent's place at the time, her brother and one of his friends, Ghosh added.