Section 56(b) in Police Regulations, Bengal , 1943
(b)An officer supervising an investigation shall keep a personal diary in the form prescribed for Inspectors in regulation 197 and shall note in the manner in which he supervised the investigation, any questions which he has put to a witness, any identification which took place in his presence and any other matters on which he may need to refresh his memory before giving evidence. This diary shall be kept in the officers' personal custody.
