The case of R.M. Malkani v. State of Maharashtra is related to which of the following?

In R.M. Malkani v State of Maharashtra (1973) the Supreme Court held that a contemporaneous tape record of a relevant conversation is a relevant fact and is res gestae, admissible under sections 7 and 8 of the Indian Evidence Act (now sections 5 and 6 of the Bharatiya Sakshya Adhiniyam, 2023), provided the voices are identified and the accuracy of the recording is proved. The case is therefore studied with the relevancy of facts that form part of the same transaction.