Police said they detained three people after recovering the bodies of a woman and her son from the septic tank of a rented house in Sherpur on Thursday.
The deceased were identified as 35-year-old nurse Roksana Begum and her 11-year-old son Md Rafid. Police detained Masek Ali, a "drug addict" auto-rickshaw driver, his mother, and another person over the incident.
According to police, Masek used to live with Roksana and Rafid at a rented house in the Nabinagar Panaitapara area of Sherpur town.
Roksana's elder sister Sufia Begum filed a general diary (GD) at Sherpur Sadar Police Station on Wednesday after Roksana and Rafid had gone missing on December 4.
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"We found Masek's involvement in the killing after questioning him. Later, police conducted a search of his house and found the bodies inside the septic tank. We've detained Masek, his mother and another person in connection with the killing."
"We think a dispute between Masek and Roksana over money for buying drugs led to the killing," Md Hannan Mia, additional superintendent of police of Sherpur Circle, said.
Bashir Ahmed Badal, officer-in-charge (OC) of Sherpur Sadar Police Station, said the bodies have been sent to the Sherpur Zila Hospital morgue for autopsies. "Police will file a case over the killing."