Heartshot

Septuagenarian undersheriff Bill Gastner of Posadas County, N.M., is the skeptical, endearing narrator of this mystery debut by a writer of Westerns ( Timberblood ). Conscious of advancing age and his bulging waistline, Gastner distrusts both computers and the skills of newly elected sheriff Martin Holman, a former used-car salesman. When a large stash of cocaine is found in the car of five teenagers killed in a crash, local officials are stymied. A young state cop is brought in to mingle with the victims's friends, posing as Gastner's grandson. In short order, a grief-stricken father shoots the undercover cop, a moody teenager dies in a suspicious ``suicide,'' and Gastner has a heart attack. Eventually Gastner, the surprisingly capable Holman and detective Estelle Reyes expose a complicated drug-smuggling operation. Airplanes, real and model, loom large in the denouement and the climactic flying sequence is a corker. If the villain's identity is not surprising, readers still will enjoy this caper and look forward to future appearances of curmudgeonly charmer Gastner. (Mar.)