Sometime in the year 1966 on information lodged at the instance of opposite party No. 1, the Detective Department of the Calcutta Police took up investigation into a case involving offences of cheating, forgery, conspiracy etc. against the present petitioner. In April 1967 the petitioner filed a complaint against opposite parties 1, 2 and 3 in the court of the police magistrate at Alipore alleging similar offences. The learned magistrate sent the complaint to the officer-in-charge of Watgunge police station for investigation. The order was made obviously under S.156(3) of the Code of Criminal Procedure. Subsequently, it appears, the investigating officer who was investigating the case earlier instituted at the instance of opposite party No. 1 moved the Deputy Commissioner of the Detective Department praying that that case as also the case of the Watgunge police station referred to above may be investigated by the same officer. On July 20, 1967 D. C., D. D. approved the proposal and directed one sub-inspector Seal, the investigating officer of the earlier case, to take up investigation of the Watgunge police station case too. Sub-Inspector Seal took up investigation of the othe