The End of the Web by George Sims
Leo Selver, a middle-aged antiques dealer, is stunned when the beautiful and desirable Judy Latimer shows an interest in him. Soon they are lying in each other's arms, unaware that this embrace will be their last. Popular opinion suggests that Leo murdered the girl, a theory Leo's wife - well aware of her husband's infidelities - refuses to accept. Ed Buchanan, a former policeman who has known the Selvers since childhood, agrees to clear Leo's name. Selver and his fellow antique dealers had uncovered a secret and it is up to Ed to find the person willing to kill in order to protect it. This exhilarating and innovative thriller was first published in 1976.