Soumen Kumar Roy, the suspended assistant sub-inspector of police confessed to shooting his wife, her child and a young man to death in a statement before a court on Monday.
The victims of the gruesome crime were Soumen’s wife Asma Khatun, son Robin and bKash agent Shakil Khan who were killed in broad daylight in Kushtia city.
Soumen, the lone accused in the triple murder case, confessed under Section 164 in the court of Kushtia Additional Chief Judicial Magistrate Enamul Haque.
Later the court sent him to jail pending trial.
The policeman confessed that he had committed the crime as he could not accept the "extra-marital affair of his wife Asma with bKash agent Shakil."
He also told the court that he left his workplace without permission and came to Kushtia early Sunday from Khulna by bus and brought a service pistol and bullets with him.
He said he wanted to take Asma to Khulna, but she refused to go with him. At one stage of altercation with Asma, Soumen got furious and opened fire before gunning down seven-year-old Robin and 28-year-old Shakil.
Panicked the boy tried to run away, but Soumen caught him before shooting the boy dead.
The shootings took place at a market in the district town's PTI Road around 11 am.
As the locals came to the rescue, Soumen threatened them with his weapon. Later, people began attacking him with stones and brickbats.
The gun-wielding Soumen then threw down his weapon and locals took him into custody before turning him over to the police, according to Kushtia Model Police Station Officer-in-Charge Sabbirul Islam.
The victims were rushed to Kushtia General Hospital, where they were declared dead.
On Sunday night, Hasina Khatun, mother of Asma, filed a case over the incident with Kushtia Model Police Station, said Sabbirul Alam, officer-in-charge of the police station.
Meanwhile, the bodies of Asma, Robin and Shakil were handed over to their families midnight Sunday.
"ASI Soumen Kumar is from Magura and was assigned to Khulna's Fultala Police Station," he added. Asma's brother Hasan said her sister was Soumen's second wife.
Soumen went to Kushtia without any official authorisation and killed three people there, said Khulna Superintendent of Police Mahbub Hasan. "The ASI was not on leave. He has been suspended and legal actions will be taken against him."