Report No. 87
3.16. Voice prints furnish one example of physical evidence not dealt with by the Act.-
Often, it becomes desirable to have an accused person speak for the purposes of giving to the police an opportunity to hear his voice and try to identify it as that of the criminal offender. A comparison may even be desired between the voice of an accused person and the recorded voice of a criminal which has been obtained by, say, telephone tapping. To facilitate proof of the crime the police may like that the accused should be compelled to speak-and even that his voice as recorded may be converted into a 'voice print.'1-2
Words so compelled to be spoken for the purposes of comparison may not amount to testimonial compulsion with the scope of the constitutional privilege against self-incrimination as now understood, so long as the matter which the accused is compelled to speak does not relate to the crime.3 They represent really evidence of a physical nature. The accused, by speaking such words, is giving merely "identification data", and is not subjected to any "testimonial compulsion."
However, if the accused refuses to furnish such voice, there is no legal sanction for compelling him to do so, and the use of force for that purpose would be illegal.
1. Cf. R. v. Reating, (1909) 2 Cr Appeal Reports 61.
2. See Thomas McDade The Voice-Print, (July 1970), Indian Police Journal, pp. 26-34.
3. Compare Inbau Self-incrimination, (1950), p. 51, referred to by Moreland Criminal Procedure, (1959), pp. 78-79.