Jamshedpur: Four members of a criminal gang were arrested from a primary school campus in Gadra under Pursudih police station limits on Wednesday.SP (city) Kumar Shivashish said that three members of the gang were plotting extortion and robbery at the school ground, when police conducted a raid based on a tip-off.Roshan Singh alias Paka, 30, Roshan Kumar alias Bangali, 23, and Azad Pal alias Babu, 27, were caught from the spot, while gang leader, Shivnarayan Razak, 30, was arrested from Barigora in Pursudih. A country-made pistol and three live bullets were recovered from them.The gang’s plan was to orchestrate multiple extortion and robberies, to create terror and carve out a space for themselves in the crime world, police said.The SP said that all the four have five to nine criminal cases registered against them. Roshan is an externed criminal. They have been sent to jail.