By Robert Reuland

Random House. 242 pp. $24.95

Robert Reuland's finely crafted second novel tells of a prosecutor named Andrew Giobberti who, at the outset, has lost almost everything. He lost his 5-year-old daughter to a traffic accident and his wife to divorce. After unwisely freeing a woman who proceeded to kill her child, he lost his job as a prosecutor of homicide cases in the Brooklyn district attorney's office and was banished to the purgatory of the appeals bureau. After 18 months of boredom and humiliation, he is abruptly summoned to prosecute a teenager accused of killing the owner of a bodega in a botched holdup.

Gio, as he is known, wants desperately to return to homicide, for his self-image is that of "a man who tried men who killed men," and yet he knows something is wrong with this case. Why else would the duplicitous district attorney, who has the unfortunate name Fister, have summoned him from exile if not to make him a fall guy? Still, Gio agrees to work the case along with an inexperienced prosecutor, a beautiful young African American named Laurel Ashfield. The two can barely communicate. He is white, 40, angry, cynical; she is naive, idealistic, suspicious, withdrawn. Their relationship is difficult, but they move slowly toward trust and toward an agonizing decision, as the problem with the case emerges.

A fix is in, made by the police, sanctioned by the district attorney. To convict the defendant, who has killed several people, they must use a witness they know is lying; if the witness tells the truth, the killer will go free. Gio and Laurel must battle both their bosses and their consciences. Accepting the frame-up is the price Gio must pay to win his return to the homicide office. "There are only wrong moves left," he tells Laurel.

The only thing wrong with this novel is its bang-bang title, which suggests a different kind of story. "Semiautomatic" is notable not for violence but for subtle characterizations, moral ambiguities and exceptional writing. Reuland has been, like Gio, a prosecutor in Brooklyn. Many lawyers publish novels these days, and most express themselves with clarity. But not many lawyers (or non-lawyers, for that matter) produce fiction that is fresh, surprising and lyrical, as Reuland does. Some readers may find "Semiautomatic" too inward for their tastes, but in stylistic terms it's the best-written legal thriller I've ever read, hands down.

On page after page, there are small grace notes. A nasty old judge lusts after Laurel "only in darting hooded glances." That judge, without his black robe, "is the janitor again." A juror "has the soft, indistinct features of someone who owns cats." A dying man looked bad before, but "now he is circling the drain." A shyster lawyer's "tie has gone belly up, a dog wanting a scratch." A teenager is "big and doughy, all curves, as if he has been scooped up and dropped into the chair with a spatula." A lawyer talks "in pure fluent low-rent legal," and Laurel's "politeness has teeth that bite." Gio remembers how his wife would go shopping and "fill our crappy little Honda until it raised its nose like an inquisitive pig." As he moves about Brooklyn, remembering homicides past, "the borough is, for me, awash in blood, and there are some blocks where I cannot shake the ghosts in certain doorways and vacant lots, on stoops and manhole covers. All around them, unaware, children play. Women push strollers and shop. Old men sit on benches where dead boys leer at them. From my car window I see them. Do the living not know, or do they forget? And if they have forgotten, how do they do it? I would like to know." You don't often see writing like that in thrillers. Reuland's sensibility is closer to John Updike's, say, than to John Grisham's. Yet he never lets us forget that he is a lawyer, if one with a touch of the poet:

"I loved standing up. I loved picking a jury, winnowing out the twelve solid citizens who could do business. I loved making an opening statement, telling my jurors how I would tear away the thin veneer of civilization that separated them from the man over there. I loved the judges who slept during testimony. I loved the defense lawyers who worked [with] what they had and knew the score. I loved the witnesses who hated my guts. The cops who never showed up when I needed them, but, when they eventually did, would sometimes bring a cup of coffee as an apology. The families of the dead boys. The mothers and sisters and aunts who came to court dressed as if for church and looked to me with unreasonable hope and apologized oftentimes and . . . " The passage goes on but you get the idea. This is a different sort of legal thriller, one for readers who understand that good writing is the biggest thrill of all.