As cowgirl-turned-quilter Benni Harper might have expected, marriage to San Celina (Cal.) police chief Gabe Ortiz is no bed of roses. On her maiden voyage to Derby, Kansas, to meet her bridegroom's family, she finds them up to their Stetsons in murder. Local feed-and-grain scion Rob Harlow's newest girlfriend, country singer Tyler Brown, has been bashed to death with a brick, and everyone in town is a suspect. It's an especially rich field, since Tyler was AWOL from an Amish husband who couldn't get divorced as long as she lived, and her current activities weren't calculated to win new friends. Despite her distracting misgivings about her own husband's secrets, Benni's sharp eye for quilt patterns provides the crucial clue. And for that matter almost the only clue in Benni's third outing (Irish Chain, 1995, etc.), more notable for its double- wide raft of suspects and its affectionate prairie background than for its tight plotting.