Detective Sgt. Wright, winger for Supt. Kenworthy--he of the withering put-down and oily artistry in interrogation--is allowed to take the lion's share of house-to-house interviews among the edgy Margerum clan. It's Margerum family history that seems to be the wild card in the hunt for the murderer of an elderly spinster scholar, found swinging on a floating hangman's drop by the seashore. The raw East Anglia climate and salty local dialect keep this from going out with the tide.