Kushtia police arrested Nowroz Kabir Nishat, nephew of the slain school teacher Roksana Khanam as her lone killer.
The murder took place as Roksana prevented Nishat from playing online betting.
Nishat, 19 was son of Roksana's younger brother late Imranul Haque.
A team of Detective Branch (DB) arrested Nishat on Monday night. Nishat and his family was living at Roksana’s house.
Kushtia DB Police Officer-in-Charge Nasir Uddin confirmed the matter.
The DB official said Nishat confessed to the murder during the preliminary interrogation.
According to the confession, Nishat killed Roksana by hitting her on the head with a hammer while she was sleeping.
Roksana Khanam is a teacher on English at Kushtia Zilla School. Her body was recovered from her residence on Monday morning.
According to family sources, after the death of Nishat's father, Nishat lived with her mother and one sister at her aunt Roksana's six storied house and Roksana was raising Nishat on her own. Roksana bought for Nishat a motorcycle worth Tk 1 lakh 90 thousand a few months ago.
The OC said Nishat was addicted to drugs and gambling. He reportedly sold the motorcycle Roksana gave him in gambling. Roksana scolds Nishat about this.
OC continued that still Nishat kept demanding money from Roksana on various excuses. Nishat gets angry when Roksana refuses to pay the money.
Roksana talks with Nishat on Monday as well.
OC Nasir said after Rosana’s refusing of giving money, Nishat decided to kill her.
On Sunday evening, when Roksana went to the roof of her house, Nishat took chance and entered into a room and hide himself. When Roksana fell asleep, Nishat killed her by hitting her on the head with a hammer at around 1:30 am.
Nishat also told the police that after the murder, he sent a few messages from Roksana's mobile phone to his mobile phone. There was a mention of rushing to the bus stand in the morning.
OC said when Roksana was lying on the ground in a bloody state, Nishat ransacked the house to divert the incident. After the murder, Nishat got out through a round hole on the balcony of the house.
Police recovered the hammer used in the murder from the elevator room.
Roksana reared this Nishat and was nurturing him like her own child. Roksana had no children.
DB Police OC Nasir Uddin said that three members of the family were detained for questioning
in the murder.
Kushtia Model Police Station Inspector (Investigation) Zahurul Islam said that the victim's husband Khandkar Mostafizur Rahman is preparing the case.