Members of Rapid Action Battalion (Rab) arrested four people for repeatedly raping and blackmailing a teenager in Kathiapara area of Gomostapur upazila.
The arrestees were identified as Nishan Ali and his associates Jahurul Islam, Shamim Reza and Himel.
Company Commander of Rab-5 Chapainawabganj Camp ASP Azmal Hossain said Nishan had an affair with the victim and he recorded their intimate moments on phone.
Nishan and his accomplices had been repeatedly raping the girl and blackmailing her for the last seven months, he said.
The victim, unable to bear the torture, finally informed her family and they filed a complaint, the Rab officer said.
He said they seized mobile phone, video footage, pen drive and laptop from the accused.
A case was filed at Gomostapur Police Station over the matter.