law: 155. Information as to non-cognizable cases and investigation of such cases.-
  (1) When information is given to an officer in charge of a police station of the commission within the limits of such station of a non-cognizable offence, he shall enter or cause to be entered the substance of the information in a book to be kept by such officer in such form as the State Government may prescribe in this behalf, and refer the informant to the Magistrate.
  (2) No police officer shall investigate a non-cognizable case without the order of a Magistrate having power to try such case or commit the case for trial.
  (3) Any police officer receiving such order may exercise the same powers in respect of the investigation (except the power to arrest without warrant) as an officer in charge of a police station may exercise in a cognizable case.
  (4) Where a case relates to two or more offences of which at least one is cognizable, the case shall be deemed to be a cognizable case, notwithstanding that the other offences are non-cognizable.