The group led by JU JCD Assistant General Secretary Ehsanul Huque Ashish, Maruf, Swapnil, Sagar and Sumon along with four or five outsiders, believed to be Islami Chhatra Shibir (ICS) activists, stormed room no 243 of the hall at 2:15am in search of JU BCU convenor Rakibul Alam Rusho, sources said.

Not finding him, they beat up Azad, Sumit Kumar Chanda, Shateel Kabir and Ashraful Alam Chanchal, third year final examinees of Drama and Dramatics, and vandalised a computer set and cell phone sets they found in the room.

Rusho ran to the third floor of the hall and took shelter in a friend's room where the attackers followed him and mercilessly beat with iron rods, hockey sticks, hammer and sharp weapons until he collapsed on the ground.

They also stabbed above the heels in an attempt to cut his tendons but failed as general students and other JCD activists thronged the scene and caught hold of the attackers.

Rusho was taken to Dhaka Medical College and Hospital from where he was shifted to Health and Hope Hospital in Dhaka.

His condition is stated to be critical.

The other injured were given first aid at the university medical centre.

Meanwhile, Sumon, one of the attackers, who was beaten up by the hall JCD activists, was admitted to Enam Medical College Hospital.

Later, Proctor Prof Kamrul Ahsan took charge of the attackers and released them shortly afterwards.

Hall Provost AKM Shahnawaz at an emergency meeting yesterday formed a three-member probe body that was asked to submit report by September 9.

General activists of JCD and left-leaning student organisations fear that the way the group made the attack might be an indication of ICS's attempt to revive its activities on the campus.