UNB, Rajshahi :Inspector General of Police (IGP) Hassan Mahmood Khandker on Saturday said police are investigating the murder of Rajshahi University teacher Shafiul Islam with a special priority.”I hope the motive behind the murder will be debunked soon,” he said while talking to reporters after a programme at Bangladesh Police Academy at Sarda.”Sometimes police get clues immediately after the incident but sometimes it takes time to have clues. But I’m sure the mystery behind the murder will be debunked soon,” he added.He said, they are investigation the facebook status of Ansar-Al-Islam Bangladesh-2, a suspected militant outfit, which claimed responsibility for the murder.All the necessary measures have been taken to maintain the law and order at the Rajshahi University, the police boss said.Prof Shafiul Islam was stabbed by some unknown assailants on his way home at Chouddapai near the RU campus around 3:30 pm on November 15.He succumbed to his injures at the Intensive Care Unit of Rajshahi Medical College Hospital half an hour later. Meanwhile, police detained 20 people in connection with the killing of Prof Shafiul Islam on November 16. A court here on Wednesday placed 11 people on a two-day remand in connection with the murder.RU Registrar Eltajul Haq filed a case with Motihar Police Station following the murder.