A gang of masked criminals stabbed a trader dead in front of Parveen Public School in the district town on Friday night. The deceased, Siraj Pathan, had a cosmetic business at Chinabazar in the town. Police said the gang waylaid a motorbike riding Siraj and his friend Nazrul near the school at Diarbhita at about 10:30pm. Later, the gang stabbed Siraj and Nazrul indiscriminately, leaving them critically injured. They were whisked off to Rajshahi Medical College and Hospital where Siraj died after sometime. The reason behind the attack could not be known immediately, said police.