Maling, snappily engaging author of the Brock Potter mysteries series (Lucky Devil, etc.) and other suspense fiction (The Rheingold Route), now introduces Chicago shamus Calvin Bix--in a smoothly narrated investigation that starts out distinctively but later slides downhill into very routine matters. Initially, Bix is hired by rich, middle-aging widow Anita Danton to find her handsome young lover Peter Ives--who has disappeared with some of Mrs. D.'s jewelry. Sleuthing in and around Ives' apartment-building, Bix soon learns that Ives was recently the target of an attempted sniper-killing, and that he was mixed up in some enigmatic money-laundering scheme (subject of a federal prosecution). Then, suddenly, Bix's job seems to be over: Ives turns up dead in Mrs. Danton's town-house garage. When Mrs. D. herself becomes a murder suspect, however, Ives is re-hired--to get the goods on the real killer, a shadowy assassin known as ""Sparrow."" The trail leads to Tucson, where Ives got involved in shady doings (ho-hum drugs stuff) at a creepy resort. And when Bix himself becomes the target for Sparrow & Co., he shrewdly seeks out the Zurich super-dealers behind the entire money/drugs network. . .before winding up in a predictable showdown with psycho-hit-man Sparrow. Bix, blending some lightly sexy romance (a post interior decorator) with the rough stuff, is a breezy, unforced narrator. Some of the supporting characters (e.g., a prim Indian waiter) and backgrounds (the Chicago-socialite scene) are memorably sketched, But, after an intriguing first half, the plot becomes increasingly drab, without surprises or tension--making this very professional job a disappointment, especially for Mating fans.