Northern Italy is the milieu for two solid police-procedural series from British writers: Timothy Holme's adventures for Venice's suave Achille Peroni (At the Lake of Sudden Death, p. 1274) and Williams' more somber, more convoluted cases, featuring older, sadder Commissario Trotti of Milan (The Red Citroen, The Metal Green Mercedes). This time Trotti is investigating the strange knifing (non-fatal) of little Laura Vardin, sleeping on the sofa, by a dark-of-night intruder. Was the attack a failed rape? Was the intended victim really Laura's 17-year-old sister Netty, who usually slept on that sofa? Was the culprit Netta's randy boyfriend? Or an ex-con with a grudge against Laura and Netta's father? Or a random psycho? (An aging spinster suffers a similar attack soon thereafter.) Trotti follows all the leads with grim doggedness--especially after devoted policewoman Ciuffi is sniper-killed during their sleuthing. But he is repeatedly distracted by reports of ugly doings from his hometown in the hills: a series of killings that's connected to WW II secrets involving ruthless fascists and murdered partisans (including Trotti's beloved older brother). And, while being shot at and kidnapped by assorted villains, Trotti also has more personal matters to brood on: departmental rivals, his estranged wife and daughter, his longing to adopt a baby son, the obliquely seductive ways of various women. The hometown, subplot is an ungainly complication here, particularly since it's delivered in talky chunks of melodramatic exposition. Still, with offbeat dialogue, curious sidelights (an old policeman's dying dog), and a convincing psycho-solution to the central mystery, this thick Italian tangle is edgily absorbing and darkly rewarding.