The Flaxborough Crab - Colin Watson

First published 1969; cover shown is the 1991 Mandarin Paperbacks (UK) edition. Cover design by Button Design Co.

One female after another in Flaxborough, a quiet town in the east of England, is becoming the victim of sex-crazed maniacs. Groped in the street, preyed on in the woods, chased through meadows, watched by trouserless men through windows, forced to listen to dirty talk in the church vestry... Detective Inspector Purbright and his legion of constables have their work cut out for them. The only clues are that the attacker is elderly (he smells like cough medicine and has "dry, bony" hands) and that he runs in a very strange manner: sideways, like a crab.

When the local alderman decides to chase a terrified woman in the middle of a hide & seek game at a senior citizens country outing, slips after "running like a crab" and drowns in the reservoir, Purbright believes the women of Flaxborough are safe once more. But within hours of the inquest a young schoolteacher looks out her bedroom window to see a trouserless man looking in. He scuttles away "like a crab" and Purbright has no choice but to reopen the investigation.

The inquest held after Alderman Winge's death uncovered a new line of inquiry for the police: Winge had been taking a locally-made herbal remedy known as Samson's Salad, thought to increase "vigour" in the over-60s. Winge's doctor, Meadow, blames this concoction for his patient's unseemly activity, although Purbright soon discovers that the doctor himself has been dispensing suspect drugs to a number of his elderly patients. Something is turning the geriatic community of Flaxborough into sex-crazed fiends... but is it Samson's Salad, or the untested medical drug? And why does Dr Meadow soon after die mid-consultation, his last words being "The fur's darker?"

This was one of the best mysteries I've read in a while - and the funniest! The town of Flaxborough seems average enough... but it's a superficial averageness, barely masking the realistic, dirty and violent underbelly that Watson somehow keeps you completely aware of all the way through.