(A) Delhi Special Police Establishment Act (25 of 1946) , S.2— Central Bureau of Investigation (Crime) Manual (2005) , Para.9.1— Preliminary enquiry - In cases of corruption - Is not mandatory before registration of FIR under Cr.P.C., Prevention of Corruption Act or even CBI Manual - In case information received by CBI through a complaint or a "source information" discloses commission of a cognizable offence, it can directly register a regular case instead of conducting a preliminary enquiry - Said formulation does not take away from value of conducting a preliminary enquiry in an appropriate case. Criminal P.C. (2 of 1974) , S.154— Prevention of Corruption Act (49 of 1988) , S.13(1)(e), S.13(2)— Penal Code (45 of 1860) , S.109— Two distinct principles emerge from Para 9.1 of CBI Manual that (i) a preliminary enquiry is registered when information (received from a complaint or "source information") after verification indicates serious misconduct on part of a public servant but is not enough to justify the registration of a Regular Case; and (ii) when the information available or after its secret verification reveals the commission of a cognizable offence, a regular case has to be registered instead of a preliminary enquiry being resorted to necessarily. Para 9.1 of CBI Manual notes that a preliminary enquiry is required only if the information....