Section 652(b) in Police Regulations, Bengal , 1943
(b)Certificates so granted shall remain in force for three years only from the date of issue and can only be renewed if the officers holding them return to the Finger Print Bureau for a period of not less than one week, and satisfy the Assistant to the Deputy Inspector-General that they have retained their knowledge and are still fit to hold the certificate. It shall not be necessary for officers attached to the bureau to renew their certificates of efficiency after three years.
