Do polygraph tests actually work?

Although not a professional police officer himself, Keeler carried out his own investigations – he invited one murder suspect to a faked Ku Klux Klan meeting and used the polygraph on him, telling him it was part of an initiation ceremony – and was prone to informing the press that the machine would soon bring about a 100 per cent crime clear-up rate and make juries obsolete. This infuriated Larson, who thought Keeler’s crankish-sounding pronouncements ensured the continuing inadmissibility of polygraph readings in court.

Katwala’s book is something of a grab bag itself. As well as presenting us with potted biographies of Vollmer, Larson and Keeler and detailing their fallings-out, it also recounts the ins and outs of two murder cases in which, Katwala maintains, the polygraph contributed to two probable miscarriages of justice. (Based on the evidence he musters, I would downgrade his probable to possible; but he certainly demonstrates how easily the polygraph can be manipulated, unconsciously or otherwise.)

Indeed he goes into these murders, and the lives of the suspects, investigators, lawyers and so on, in such detail that the polygraph and its inventors often vanish for dozens of pages at a time; and although his narrative deploys its twists and maintains suspense with some skill, the connoisseur of true crime may wonder if these two cases are really worth such extensive treatment.

The book is at its most interesting when dealing – with greater concision – with some of the other strange cases that came the polygraph’s way, including that of William Hightower, a nutter who murdered a priest for no good reason. Some incidents deserve more coverage – the man who suddenly threw himself out of an eighth-floor window in the middle of one of Keeler’s polygraph tests surely merits more than one sentence.

Katwala tells his various tales with admirable lucidity, only occasionally lapsing into the portentous purple prose beloved of true-crime writers, and the book is rich with colourful incidental detail. He is wise to quote liberally from US newspapers of the period, with their sublime epithets: one judge who had a habit of allowing attorneys to leave early when their wives were due to give birth was dubbed “aid to the stork”.

In a worrying coda, Katwala points out that our current government has abandoned previous Lord Caterham-esque cynicism to authorise the increased use of polygraph machines in police work. We now have artificially intelligent lie detectors, which are supposedly more accurate. But has anyone invented a machine that tells you if the machine is fibbing?


Tremors in the Blood by Amit Katwala is published by Muldark at £20. To order your copy for £16.99 call 0844 871 1514 or visit books.telegraph.co.uk

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