Dhaka: Members of Rapid Action Battalion (Rab) in Gopalganj have arrested the prime suspect accused of murdering a businessman's first wife along with their youngest son in the city's Kakrail area.

With the arrest of Al Amin alias Jony, brother of the businessman's third wife Sharmin Akhter Mukta, all the accused in the case filed by the victim's brother with Ramna Police Station have now been arrested.

Director (Media and legal wing) of the Rab headquarters Mufti Mahmood Khan told UNB that acting on a tip-off, a special team of Rab-3 conducted a drive at Muksedpur in Gopalganj and arrested Jony around 3:30 am on Saturday, he said.

Sources at the Rab-3 battalion headquarters said during preliminary interrogation, Jonny confessed his involvement in the double murder, including:

That he bought a sharp weapon for Tk 1100 from a New Market shop on October 31, and took it home to Nayapaltan.

On the day of the murder, November 2, he came out of his Nayapaltan residence at around 4:30 pm carrying a bag that contained the cleaver he bought, one lungi and one t-shirt.

He kept the bag, with the change of clothes still inside it, in an under-construction building on the way, and proceeded with the cleaver to the flat of Kakrail VIP road to kill Shamsunnahar.

The door to the flat was opened by Shamsunahar's maid, after Jonny said he rang the bell. As soon as she returned to the kitchen however, Jonny shut the door behind her and then he swooped on Shamsunnahar in her bedroom. Her body was found with multiple stab wounds lying beside her jaynamaaz (prayer rug). It was just after Maghrib.

As Shaon, Shamsunnahar's youngest son, appeared unexpectedly on the scene, Jonny attacked him as well with his cleaver, leaving him dying on the stairs.

Jonny then fled scene, returning first to the under-construction building where he kept his change of clothes.

He has provided a dispute over property between his sister Mukta and Shamsunnahar.

Ashraf Ali, brother of victim Shamsun Nahar, filed the case with Ramna police station on Thursday night accusing Abdul Karim, 56, husband of victim Shamsun Nahar, his third wife Sharmin Akhter Mukta, 25, Mukta's brother Al Amin alias Jonny, 33.

Police earlier arrested Abdul Karim, and his third wife Sharmin Akhter Mukta soon after the killing on Wednesday night.

They are being interrogated by Ramna thana police as a Dhaka court on Friday placed them on 6-day remand in the case .

On Wednesday, Shamsun Nahar, 40, 1st wife of Abdul Karim, and their son Shawon, 22, were found killed at their flat in a multi-storey building in the city's Kakrail area.