An unidentified group hurled a petrol bomb at Mahendra Morang Campus in Biratnagar, Morang, on Thursday night. The group had bombed the examination department of the campus at around 8:00 pm. No damage or casualty was reported in the incident. A police team deployed from Area Police Office, Biratnagar, immediately doused the fire. Search for the group and detailed investigation into the bombing is under way, said police.