This question arose before a Division Bench of three judges in an appeal carried by the State of West Bengal in the case of State of West Bengal v. S. N. Basak, Kapoor, J. quoted with approval the observations of the Judicial Committee in the case of king Emperor v. Khwaja Nazir Ahmad, where the Privy Council observed:
“The functions of the judiciary and the police are complementary, not overlapping, and the combination of individual liberty with a due observance of law and order is only to be obtained by leaving each to exercise its own function, always, of course, subject to the right of the Court to intervene in an appropriate case when moved under s. 491 of the Criminal Procedure Code to give directions in the nature of habeas corpus. In such a case as the present, however, the Court’s functions being when a charge is preferred before it, and not until then.
It has sometimes been thought that s. 561A (now s. 482) has given increased powers to the Court which it did not possess before that section was enacted. But this is not so, the section gives no new powers, it only provides that those which the court already inherently possesses shall be preserved and is inserted as their Lordships think, lest it, should be considered that the only powers possessed by the Court are those expressly conferred by the Criminal Procedure Code and that no inherent powers had survived the passing of that Act.”
The Court added: “With this interpretation, which has been put on the statutory duties and powers of the police and of the powers of the Court, we are in accord.” on a finding that the High Court had exceeded jurisdiction in interfering with the investigation, the appeal of the State of West Bengal was allowed.
The question again arose in the case of S. N. Sharma v. Bipin Kumar Tiwari & Ors. on this occasion the Court was called upon to examine the scope of magisterial power. After referring to the relevant sections, the Court concluded that:
“The scheme of these sections, thus, clearly is that the power of the police to investigate any cognizable offence is uncontrolled by the Magistrate, and it is only in cases where the police decide not to investigate the case that the Magistrate can intervene and either direct an investigation or, in the alternative, himself proceed or depute a Magistrate subordinate to him to proceed to enquire into the case. The power of the police to investigate has been made independent of any control by the Magistrate.”
Then came the case of State of Bihar v. J.A.C. Saldanha & ors. In a peculiar set of fact the Court was again called upon to adjudicate upon the scope of judicial interference over investigation. Speaking on this aspect of the matter, Desai, J. spoke for the Division Bench thus:
“There is a clear cut and well demarcated sphere of activity in the field of crime detection and crime punishment. Investigation of an offence is the field exclusively reserved for the executive through the police department, the superintendence over which vests in the State Government. The executive which is charged with a duty to keep vigilance over law and order situation is obliged to prevent crime and if an offence is alleged to have been committed it is its bounden duty to investigate into the offence and bring the offender to book.
Once it investigates and finds an offence having been committed it is its duty to collect evidence for the purpose of proving the offence. Once that is completed and the investigating officer submits report to the Court requesting the Court to take cognizance of the offence under s. 190 of the Code its duty comes to an end.
On a cognizance of the offence being taken by the Court the police function of investigation comes to an end subject to the provision contained in s. 173(8), there commences the adjudicatory function of the judiciary to determine whether an offence has been committed and if so, whether by the person or persons charged with the crime by the police in its report to the Court, and to award adequate punishment according to law for the offence proved to the satisfaction of the Court.
There is thus a well-defined and well demarcated function in field or crime detection and its subsequent adjucation between the police and the Magistrate.”
The observation of the Privy Council which we have already extracted were again quoted with approval, Desai, J. adding: “This view of the Judicial Committee clearly demarcates the functions of the executive and the judiciary in the field of detection of crime and its subsequent trial and it would appear that the power of the police to investigate into a cognizable offence is ordinarily not be interfered with by the judiciary.”
  2 S.C.R. 52.
  L.R. 71.
  3 S.C.R. 946
  2 S.C.R. 1 6