In the case of Selvi v. State of Karnataka, (2010) 7 SCC 263, it was held that;
Ordinarily evidence is classified into three broad categories, namely, oral testimony, documents and material evidence. The protective scope of Article 20 (3) read with section 161 (2) CrPC guards against the compulsory extraction of oral testimony, even at the stage of investigation. With respect to the production of documents, the applicability of Article 20 (3) is decided by the trial Judge but parties are obliged to produce documents in the first place. However, the compulsory extraction of material (or physical) evidence lies outside the protective scope of Article 20 (3). Furthermore, even testimony in oral or written from can be required under compulsion if it is to be used for the purpose of identification or comparison with materials and information that it already in the possession of investigators.
The term approver is neither defined nor used under Criminal Procedure Code but is usually applied to a person, supposed to be directly or indirectly concerned in or privy to an offence to whom a pardon is granted under section 306 of CrPC with a view to securing his testimony against other persons guilty of the offence. The examination of the approver under section 306(4) of the code is mainly concerned with the examination of the complainant and witness by the Magistrate, while processing the complaint under section 200 of the CrPC before setting up the process. The question of ‘Examination of witness’ arises only after charges are framed under section 228 of CrPC. As there is no express provision u/s 306(4) CrPC which permits the accused to cross examine an approver before committing the case to the Court of Session the Magistrate is not empowered to appreciate the evidence in session triable case.
Further the term “Examination’ under in section 306(4)(a) cannot be interpreted to mean ‘Examination’ as contemplated under section 138 of Evidence Act, so as to give an accused the right to cross-examine the approver, at the pre committal stage. In Suresh Chandra Bahri v. State of Bihar (2000) the Supreme Court Bench has regarded section 306(4) as mandatory provision and observed that the object and purpose in enacting this mandatory provision is obviously intended to provide a safeguard to the accused in as much as the approver has to make a statement disclosing his evidence at the preliminary stage before the committal order is made and the accused not only becomes aware of the evidence against him but he is also afforded an opportunity to meet with the evidence of an approver before the committing Court itself at the very threshold.
In no stretch of circumstances the cross examination which is contemplated under section 306(4) of the Code can be equated with the ‘examination of witness’ under section 138 of Evidence Act. where u/s 305 CrPC when an approver is being examined by a Magistrate, he is merely recording his statement after grant of pardon and as such he merely acts as a post office by recording a statement u/s 306 CrPC and thereafter forwards it to the court of session which is the court competent to try the case and therefore the term ‘examination’ used in section 306(4) cannot be equated with the term ‘examination of witness’ meant u/s 138 of Evidence Act.