Section 4A(1)(b) in The Calcutta Suburban Police Act, 1866
(b)to the best of his ability, to obtain intelligence concerning the commission of cognizable offences, or designs to commit such offences and to lay such information and to take such other steps, consistent with law and with the orders of his superiors as are best calculated to bring offenders to justice or to prevent the commission of cognizable offences, or the commission of non-cognizable offences, within his view