Publisher's Weekly
From a simple but intriguing academic premise, Cooper (Rotten Apples, etc.) constructs an engaging puzzle based on modern police science for her seventh Willow King mystery. English amateur sleuth and romance novelist Willow helps her wealthy friend Emma who, at work on her postgraduate criminology degree, is trying to find original material about lie-detectors and their usefulness in determining a suspect's guilt. What she seeks is a definitive miscarriage of justice. Willow, married to a police superintendent, uses her connections to find the odd case of Andrew Lutterworth. Convicted of killing a mother and baby in a car accident, Lutterworth at first denies and then confesses to the crime. But at the trial, he pleads innocent. When Emma first hooks him up to the polygraph, she is led to believe he is trying to hide something, although not necessarily his role in the crime. Digging into the case, Willow and Emma learn that Lutterworth's only child died unexpectedly of necrotising fasciitis, after which his wife apparently went mad. Further lie-detector tests on Lutterworth reveal his long-hidden secret and the reason for his contradictory behavior. In the meantime, Emma strengthens her friendship with Willow. With her deft characterizations and intriguing puzzle, Cooper provides a representative example of a fine British cozy.

Library Journal
Romance writer Willow King, now married and a mother, assists longtime friend Emma, a postgraduate student in criminology, with her thesis. Emma wants to prove whether or not a man convicted of hit-and-run manslaughter gave a false confession. Elegant style; deeply satisfying series.

Kirkus Reviews
"I'm wholly disinterested. I just want to know what happened," says Emma Gnatche, and she just may be right. As part of her research for her thesis in criminology, she happens on the case of Andrew Lutterworth, an accountant who confessed to a fatal hit-and-run accident, then abjured the confession but got convicted anyway. Lutterworth still swears he's innocent, even though his insistence is probably going to lose him any chances at his upcoming parole hearing. What kind of results can Emma get from giving him a polygraph test? A bizarre surprise, since he seems untroubled by the most probing questions about the incident; it's only the innocuous control questions that send the needle skittering off the chart. Emma's friend, romance novelist Willow King (The Drowning Pool, 1997, etc.), has meanwhile dug up evidence, through a few seignorial inquiries, that bears out Lutterworth's storyþevidence the police missed four years ago. If he has nothing to hide but his grief at his son's shockingly premature death at 14, why is Lutterworth behaving so suspiciously? Despite the lead detectives' tiresome mutual self-congratulation ("You are wonderful, Willow," etc.), the marvelously edgy portrait of Lutterworthþby turns cringing, wheedling, apologizing, yet threateningþmakes this the best of Cooper's seven books.