Police on early Monday arrested a former Chhatra League leader over the reported gang rape of a housewife at remote Char Piyal in Manpura upazila.
The arrestee was identified as Nazrul Islam, 30, the former president of Chhatra League's Dakkhin Sakuchia union unit.
Sakhawat Hossain, officer-in-charge of Manpura Police Station, confirmed the arrest around 12:15am.
He said police arrested Nazrul while he was fleeing to Hatiya and seized a speedboat.
The victim was sent to Bhola Sadar Hospital for medical test, the OC added.
A case was filed against six people on early Sunday over the reported gang rape. Police said they are trying to arrest the other suspects.
The victim said she and her son, aged two and a half years, were returning home in Manpura from her parents' place at Dakkhin Aicha village in Charfasson upazila by a speedboat on Saturday. There were two other passengers on the boat.
Two more passengers got on from Janatar Khalerpar around 12:30pm, she said.
All four passengers – Belal Bepary, 35, M Rased Palowan, 25, Shahin Khan, 22, and Kiron, 26, of Rahmanpur village of the upazila – forcibly took the speedboat to Char Piyal and raped her there.
Speedboat owner Nazrul went to Char Piyal by boat and beat the four rapists.
He allowed them to go after taking Tk 3,000 from them and later raped the housewife and captured the incident on his phone.
Nazrul gave her Tk 1,000 and threatened to circulate the video if she disclosed the matter to anyone.
Finally, locals rescued the victim and took her to Manpura Police Station, said OC Sakhawat.