In the major industrialized nations the use of the human voice as an instrument in committing crimes has been steadily increasing. In Germany, this tendency has been observed for several years in a variety of offences such as extortion, kidnapping, terrorist attack, rape, hoax bomb threats and, perhaps surprisingly, in a significant number of homicide cases (59 out of a total of 538 handled in 18 months). Thus, the identification of a criminal on the basis of his/her verbal behaviour has become a challenge to our judicial systems.
However, there is considerable uncertainty on the part of the judiciary as to the degree of reliability of speaker identification (SID) by laypersons, and sometimes as to whether or not such evidence should be considered at all. Since research findings on the subject are sparse and to some degree controversial, reservations are certainly justified