Earlier in RAB's custody, they had reportedly admitted to killing the sociology department professor.
The five are former RU unit Jatiyatabadi Chhatra Dal Vice-President Abdus Samad Pintu, Katakhali municipality Jatiyatabadi Juba Dal leader Ariful Islam Manik, Al Mamun, Sirajul Islam alias Kalu, and Md Sabuj Sheikh.
Motihar Police Station OC Alamgir Hossain presented them before different courts on Tuesday afternoon. Hossain, investigating the murder case, pleaded to record their confessional statements under Section 164 of the Code of Criminal Procedure (CrPC).
"But they refused to provide confessional statements," Rajshahi Metropolitan Police's Deputy Commissioner Tanvir Haider told bdnews24.com.
He said the arrestees were brought to the courts only after they had agreed to confess.
Two of them were presented before Metropolitan Magistrates Court-2, two others before Court-3 and the fifth before Court-5.
Police, however, did not present one rickshaw-puller Ibrahim Khalil alias Tokai Babu who was also nabbed with the five.
RAB at a press briefing on Sunday had claimed these six were the real killers. They were arrested during overnight raids on Saturday and Sunday in Dhaka and Rajshahi.
At the media call, Ariful Islam Manik had admitted to killing Prof Islam on Nov 15 near his house in Chouddapai area, adjacent to the campus. He also mentioned several others who were involved in the killing.
Police had earlier said that 'Jamaat-e-Islami-controlled militants' were behind the murder, but RAB on Sunday claimed Islam was killed in an act of personal revenge.
Rajshahi police, so far, have arrested 11 people and are currently interrogating them. They have also differed with RAB's assertion and decided to continue their investigation on different leads.
APP creates confusion
Meanwhile, Rajshahi Metropolitan Court's Assistant Public Prosecutor (APP) Sushant Sarkar is alleged to have provided the media with wrong and confusing information over the five arrestees' confessional statement.
He told reporters around 5pm Tuesday that the five had confessed to their crimes in court.
Several media outlets ran reports quoting him, but Inspector Abdul Hasem later in the evening said the arrestees did not confess.
"No statements have been recorded," he added.
Journalists, however, could not get hold of Sarkar to ask about his remarks.
PP Abdul Salam said he was not sure why the APP gave wrong information to the media, but added Sarkar would face action for doing so.