Such things as telephones and tape-recorders in combination have in recent years facilitated a new set of crimes and a new type of forensic scientist has emerged to deal with them – the forensic phonetician. Two of these have produced the first book ever to describe their activities to the general public.
It reveals that there are plenty of contentious issues within the subject. For example, we find that Peter French, whose contribution is a chapter on the use of machines that analyse soundwave patterns, swears by such instruments whereas the principal author, John Baldwin of University College London, trusts confidently in his ears alone.
They are fully agreed, however, that the use (for the tracings that phoneticians refer to as sound "spectrograms") of the term "voiceprints" suggesting that they can identify individuals as reliably as fingerprints, is grossly misleading despite the media hypists eagerness to trot it out.
The book has plenty of entertaining case histories ranging from underwear-fetishism and nuisance hoax calls to poison threats, arson, blackmail, drug abuse, kidnapping and murder.
They include the story of an American crook who once thought he might get rid of forged bonds more easily to British underworld contacts by claiming to be a buddy of the Krays. However, the British police, then having a special crackdown on Kray associates, made a recording of him trying to do so and landed him in prison for a year.
One case quoted from at some length involved 300 pages of transcripts of calls of an almost unbelievable level of obscenity made by a couple from their own phone to a woman who oddly enough could never manage to bring herself to ring off despite the distress they caused her. The molesters, who protested in their defence that no-one would be so stupid as to make such calls from their own home, were detected but not finally convicted because the prosecution ran out of time before completing the assembly of their case against them!
The law apparently doesn't permit the editing of tapes to be played as evidence in court. This produced a bizarre effect when a member of a gang planning a robbery let the police equip him with a concealed recorder which he could not switch off. When his nervousness seemingly provoked an attack of diarrhoea, the result was that the court were obliged to sit listening to bowel sounds for some time before attending to vowel sounds.
On one occasion an Ulsterman fooled Baldwin so completely that his evidence, provided for the prosecution, was taken up delightedly by the defence. When it proved necessary for them to arrange a meeting between him and their client, he found that the man spoke with a totally different accent from the one he'd used when recorded by the police. He now sounded exactly like the speaker in the extortionist phonecalls he had been accused of making. He had used his southern Irish accent to the police in defiant assertion of his republican sympathies but switched to his natural Ulster style for his new "friend".
There are cases of self-styled phonetic experts (actually sound engineers etc) who made elementary errors of analysis, producing in court instrumental printouts purporting to compare the pronunciations of r-sounds not actually to be heard at all and of others (eg the e-sounds in better and problem ) which were equivalent only in spelling.
One of Baldwin's hobbyhorses is his dislike of the adversarial system of English criminal law. He feels that the expert witness should be employed not by either the prosecution or the defence but by the court. He's disgusted too that the defence can suppress evidence that is disadvantageous to its client. And he deplores the supposition he says he frequently finds that evidence based on (highly fallible human interpretation of) readings from instruments is to be valued above judgements arrived at by purely auditory observation.
The book has a few pages that are likely to be usefully informative for many members of the legal professions and police forces but at a stinging £35 for 140 pages, one could well have expected it to be better scrutinised than it has been for consistency, style, spelling etc and to have been equipped with a much more satisfactory index.
The book was published by Pinter Publishers Limited of 25 Floral Street, Covent Garden, London WC2E 9DS.