The CID team quizzed Officer-in-Charge of Gaibandha police station Noor Alam, SI Masud Rana and constables Farhad Hossain and Fahima Haider at the Circuit House for two days.

Charge sheet of the case will be submitted soon, sources in the team said.

They also interrogated Aminul Islam Golap, convener of Gaibandha Citizens Ccommittee, Farhad Abdullah Harun Bablu, Mihir Ghosh, Ahsanul Habib Sayeed, victim's father Abdur Rouf and some others and visited the Thana hazat where the incident allegedly took place.

Gaibandha police arrested medical representative Sajedur Rahman Sajid of Munshipara area in the town on May 18 last year and filed a case under the Arms Act. Police took him on seven days' remand for interrogation. SI Yousuf Ali was the investigation officer of the case.

Sajid died on the third day of police remand at thana hazat on May 22. Police first recorded a suicide case.

Father of victim later filed a murder case against SI Yousuf Ali under Section 302 of BPC alleging that his son was tortured to death in custody.

Higher police authorities had suspended IO SI Yousuf Ali, duty officer at the thana Fahima Haider and constables Dulal Chandra and Mizanur Rahman after the death.

The death triggered protests by people who brought out processions, held rallies and formed human chains in the town demanding trial of the killers. The protests were organized under the banner of Gaibandha Citizens Committee.

Later, Citizens Committee convener Aminul Islam Golap and the victim's elder brother Abdul Majed filed two cases alleging that Sajid was tortured to death and demanding probe by CID.

The court, after hearing, ordered transfer of the case to CID.