Shubal Kumar Roy, an electrician by profession, was a frequent visitor to former MP Shamsuddoha Khan Majlish's house.

He engaged in an affair with the lawmaker's daughter, Shamima Khan Majlish alias Poppy.

When MP's wife Selima Khan Majlish came to know about it, she restricted Shubal's entry to the house.

In response, Poppy allegedly stabbed her mother to death to conceal the affair, then attempted to stage the murder as an accident by electrocuting Selina with Shubal's assistance.

Banaj Kumar Majumder, the chief of Police Bureau of Investigation, yesterday confirmed the arrests of Shubal, Poppy, and house help Aarti Sarkar in connection with the murder, which took place 13 years ago.

On June 14, 2011, Selima was found injured at her home in Savar. She died at Combined Military Hospital on June 18.

Her brother filed a case with Savar Model Police Station the following day.

CID investigated for over four years, arresting three suspects but ultimately sought their exemption in a final report.

The case was then assigned to the PBI.

PBI's investigation into the murder revealed crucial evidence: a broken switchboard and a bloodstain hand mark on the wall.

"During investigation, we found out the victim was stabbed before electrocution," said  Kudrat-e Khuda, PBI Dhaka district special superintendent.

The accused, Shubol, confessed to his involvement, citing affair with Selima's elder daughter, Poppy, as motive, he added.

Elora Khan Majlish, younger daughter of the victim, said, "My sister even accompanied us to the Prime Minister's Office seeking justice. We never imagined she could kill our mother."