PARTS UNKNOWN

Burns, best-known for his Gabe Wager series, trots out Denver p.i. Devlin Kirk (Suicide Season) for a fast, laid-back sequel following the trail of three missing persons who've become involuntary donors of rare body-parts. Dev's always complaining that the agency he shares with ""Bunch"" Bunchcroft doesn't have enough work to keep solvent, but he starts off with a bang by tackling two separate cases. All right, the first is pro bono: tracing illegal El Salvador-immigrant Nestor Calamaro for a distant relative who can't pay. And it leads to the promise of more work, also for free, when Nestor's hard-as-nails landlady Mrs. Chiquichano turns out to have two other lodgers, heavily pregnant women, who've also disappeared recently. Meantime, though, Dev and Bunch have landed a job promising payment: tracking down roofer-biker Billy Taylor and taking photos of him at work and play to expose his insurance disability claim as a fraud. As Dev alternates between nocturnal skirmishes with Taylor's buddies, human and canine, and daytime phone calls that link Nestor (via his rare blood type) and the missing women (via their unborn children) to rare-organ procurers Dr. Morris Matheney and Dr. Mark Gilbert, you keep waiting for the two cases to come together--especially after Dev's place is burgled by two guys who tall and act just like Taylor's biker colleagues. Journey's end, though, will find Taylor and Antibodies Research separate casualties of justice, and Dev, his beloved Austin-Healey totaled early on, still looking for a richer case. Dev's probably right to complain that he's hardly working here, but at least he's lightened up; when that big case does come, it should be fun to watch him take it on.