M. Pinaud, master detective of the SuretY, recalls one of his early cases--officially unsolved. Years back, it seem's, pure chance took him to the small town of Vallorme and to the hunting preserve where Colonel Romand lay shot to death. A happy accident? So said the widow and a host of townsfolk--including parish priest Father La Farge--because Romand was a debauching scourge of the countryside whose victims included his 15-year-old stepdaughter (a subsequent nymphomaniac) and a woodsman's daughter (a suicide). Pinaud remembers how he saw evidence of murder but was no match for the locals' efforts to drive him out. . . and how finally, slightly more human because of the experience, he left the town and the murderer to carry on with their lives. True, Audemars may sometimes become over-infatuated with noble M. Pinaud, but the detective remains sturdily likable while the case sustains an off-beat appeal--so this is a welcome return for a veteran whose books have continued to appear in England but has been absent from the U.S. since 1966.