Section 515(g) in Police Regulations, Bengal , 1943
(g)All prisoners who remain unidentified up to the time of their release from jail, shall be interviewed after their release with a view to ascertaining, if possible, where they came from and where they are going to. The officer holding the weekly jail parade shall differentiate such impending releases by noting in red ink the word "Unidentified" in column 8, part IV, of the jail parade report, against the name of each unidentified prisoner and in the case of railway criminals shall write the words "Railway Criminals" in red ink to enable the Superintendent of Police to arrange for the interview as the prisoners come out from jail. Such persons shall, whenever possible, be shadowed or followed on their release, with a view to tracing their antecedents and ascertaining their old associates to whom they are likely to return and the result of all such action taken shall be noted in the remarks column of the register of unidentified persons (B.P. Form No. 98).
