Ullaskar was a member of the Jugantar party and he became expert in bomb-making. Khudiram Bose used a bomb manufactured by Ullaskar and Hem Chandra Das [1] in an attempt to murder the venerable magistrate, Kingsford. However, police caught many members of the Jugantar group including Ullaskar Dutta, Barindra Ghosh and Khudiram.