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.
"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."