By Robert Crais

Doubleday. 273 pp. $24.95

This is Robert Crais's ninth novel about Elvis Cole, and within the boundaries of noir -- ultra-hard-boiled, Los Angeles noir, to be precise -- it strikes me as a classic. Crais writes of a duel to the death between three professional killers who kidnap a 10-year-old boy and two equally skilled killers who set out to rescue him. The story is shrewdly plotted and sharply written, with not an ounce of fat on it, nor a trace of easy sentiment or comic relief.

Elvis Cole is a Vietnam War hero turned private investigator. His friend Joe Pike is an ex-Marine and ex-cop who says little but is lethal in action. In a prologue, Pike travels into the Alaskan wilderness in search of a brown bear ("the largest predator living on land") that has killed several people. Pike is not there for the bounty but because eight months earlier he was shot twice in the shoulder and he must test whether he has recovered the nerves and reflexes he had before. He tracks and confronts the huge bear and learns that he is not yet fully healed. The episode, with its echoes of Ernest Hemingway, demonstrates at the outset that these are men who live by a code: "He would not retreat; he would not turn away."

Meanwhile, Elvis Cole is bonding with 10-year-old Ben, the son of his lover Lucy Chenier, who is away on a journalistic assignment. Ben has stayed with Cole in his house in the Hollywood Hills and they have "cooked Thai food, watched Bruce Willis movies, and laughed a lot together." When Ben digs out Cole's box of Vietnam souvenirs, Cole gives the boy one of his Silver Stars and tells him that he is an honorary U.S. Army Ranger and that "Rangers don't leave Rangers behind." But the fun ends abruptly when Ben wanders out behind the house one evening while Cole takes a call. When Cole gets off the phone, Ben is gone.

Lucy arrives home and is both horrified and angry; this is not the first time Cole's work has brought danger into her life. A man calls and says "I have the boy" and that he is acting in revenge for something Cole did in Vietnam. The next morning, near the spot where Ben vanished, Cole finds "the partial heel print of a single shoe" in the dirt. That wisp of evidence is terrifying to Cole, because of what it says about his adversary: "It took special training and skills to hunt humans. I had known men with those skills, and they scared me. I had been one of them."

Cole tells most of the story in the first person, but at times we move to Ben in captivity. Three men have him. They bury Ben in a box underground, with only a tube to bring in air -- as, some years ago, a real-life young woman was buried in a kidnapping. The boy is brave, plotting to escape, but he is no match for the men. Ben's father, a rich and obnoxious oilman, arrives from Louisiana, accompanied by several private investigators, and angrily blames Cole for his son's plight. The police suspect Cole and tell him to leave the case to them, but he forms an alliance with Detective Carol Starkey, who was the bomb-squad expert in Crais's recent non-Cole thriller, "Demolition Angel."

Cole and Joe Pike learn that the kidnappers are three soldiers of fortune; their leader is wanted as a war criminal for his part in genocide in Sierra Leone. The man started out in the Army, first as a Ranger, like Cole, then in the elite Delta Force: "Delta trained for hard, hot insertions against terrorist targets, and membership was by invitation only. They were the best killers in the business." In case anyone doubts the kidnappers' seriousness, when the oilman sends one of his investigators to haggle over the ransom, they send back the man's head.

Cole knows what he is up against. His enemy is younger and better trained than he is and has two confederates, while Cole has only the still-wounded Joe Pike. But that doesn't matter. Motivated by love of the boy, but equally by a warrior's pride, Cole will save the boy and kill the men or himself be killed. The final confrontation between Cole and Pike and their adversaries is a stunning ballet of violence.

A story like this is hard to pull off, in part because those who live by codes so foreign to most of us are so easy to parody, as Hemingway was parodied. The writer, in addition to being skillful, must believe absolutely in the story being told, the values being honored. Crais does and, assuming always that you are open to this level of physical and emotional violence, "The Last Detective" is a rare treat.