Section 166-A Cr.P.C. deals with a situation making a request to conduct investigation outside the territories of India

During investigation of an offence the IO or any of his Superior Officer has credible information that the evidence is available in a country outside India then any Criminal Court can issue a letter of request to a Court or a competent authority in that country to examine orally the person who has acquainted with the facts and circumstances of the case and also to obtain any documents in possession of that person and the same may be forwarded to the Court who has issued letter of request.

The request letter should be forwarded as per protocol through the Central Government. Whatever collected based on the letter of request from the foreign shores shall be considered as evidence collected during the course of investigation of an offence.