The Rapid Action Battalion yesterday detained one of its members and four others for allegedly extorting money from a man at Sonargaon in Narayanganj.

The detainees are Constable Humayun Kabir, 30, of Rab-13 in Rangpur, Shahida Akhter, 45, victim's mother-in-law, Mahbub Islam, 30, a microbus driver, Hasanuzzaman, 24, brother of the vehicle's owner, and one Amjad, 31.

Lt Commander Gulzar Hossain, deputy director of Rab-11, told The Daily Star that a team led by ASP Alamgir Hossain caught the “culprits” red handed in front of the house of Mohammad Mohsin, the victim, in Narayanganj around 11:00am.

They were handed over to Sonargaon Police Station later, he said.

Gulzar said Mohsin, a Kabiraj (quack), got married to one Shilpi Begum two years ago. However, in September last year, Shilpi filed a case against Mohsin under the Women and Children Repression Prevention Act with the police station.

Later, Humayun allegedly contacted Mohsin over the phone and informed him that a complaint was also lodged against him with Rab-11.

The Rab constable also “threatened” to pick him up “soon”, if he did not pay him a “considerable amount” of money, Gulzar said.

“Humayun has already taken Tk 3.5 lakh from Mohsin in several phases over the last five months,” he said, adding that the victim had to sell his land to collect the money.

On Thursday, Mohsin contacted Rab-11 and learnt that there was no such complaint against him there.

Immediately, he informed Rab-11 about the matter and said Humayun would come to Narayanganj yesterday to collect his “last installment” of Tk 1 lakh.

Acting on the information, the Rab men detained the constable and four others inside the microbus in front of Mohsin's house.

 The Rab official said Shahida, the victim's mother-in-law, and Humayun are from the same place in Munshiganj and the entire crime was planned by the duo.

Mohsin filed an extortion case accusing five people, including Humayun, with Sonargaon Police Station last night, said Manjur Kader, officer-in-charge of the police station.