The Rab-5 also recovered a 9mm pistol from JCD leader and Vice-president of Rangpur Medical College Student Council ABM Maruful Hasan's room at the intern doctors' hostel.

Other arrestees are Ariful Islam alias Mithun, son of Azizul Islam of Dhap Kotkipara, Sirajul Islam alias Mithu, son of Ansar Ali of the same area, and Masum Miah, son of Rahmat Ali of Babu Kha.

A Rab team led by ASP Saiful Islam caught the four when they went to collect Tk 50,000 from the house of Abdul Wahed Sufi around 3:30pm, Rab sources said.

Wahed alleged Maruf and his accomplices demanded Tk 50,000 from him for his under construction building and threatened to kill him if he did otherwise.

He said, "They forcibly took me to a room of Shaheed Dr Milan Hostel of the medical college and beat up me there.

"At one stage of the torture, I agreed to give them the amount and asked them to come to my under construction house on Thursday."

He along with his wife on March 29 informed the Rab, who in the guise of day labourers took position around the house and arrested the four.

Rab and police sources said there are several allegations of crime against Maruf and his men.

Kotwali police sources said Maruf and his accomplices on March 28 abducted Zafar Iqbal alias Simu and snatched his motorcycle, cellphone and Tk 1,500. He was confined in the same hostel, from where he managed to flee with the help of other students.