As per Section 161 of Criminal Procedure Code Police offices investigating the case will examine the witnesses as per the guidelines under this section. Legal provision related to Section 161 of CRPC is:
Section 161(1) Any police officer making an investigation under this Chapter, or any police officer not below such rank as the State Government may, by general or special order, prescribe in this behalf, acting on the requisition of such officer, may examine orally any person supposed to be acquainted with the facts and circumstances of the case.
Section 161(2) Such person shall be bound to answer truly all
questions relating to such case put to him by such officer,
other than questions the answers to which would have a tendency
to expose him to a criminal charge or to a penalty or
forfeiture.
Section 161(3) The police officer may reduce into writing any
statement made to him in the course of an examination under this
section; and if he does so, he shall make a separate and true
record of the statement of each such person whose statement he
records.
Section 162 of Code of Criminal Procedure Is statement to Police to be signed. Statements of Police not to be signed