By Carlton Stowers

Pocket Books. 291 pp. $18.95

In Midlothian, Tex., in October 1987, a 21-year-old undercover cop named George Raffield was shot dead. Three kids at the high school where Raffield had been posing as a student were involved in the crime. The boy who pulled the trigger was Greg Knighten, the 16-year-old son of a Dallas police officer.

The murder was premeditated. Once the kids had "made" Raffield, they lured him, on the pretext of making a drug buy, to an isolated spot they'd chosen. Then, using the elder Knighten's police pistol, they carried out the execution. Afterward, they went to friend Cynthia Fedrick's apartment and boasted of what they'd done.

The case made headlines. Indeed, in "Innocence Lost" author Carlton Stowers describes "a steady invasion of visiting reporters, some from as far away as New York, Washington and Los Angeles, all with the same assignment: to learn the effect of a drug-related tragedy on small-town America."

Stowers has used his considerable writing skill to make what he can of this crime and its aftermath. The problem is not with the telling, then, but with the tale. The story is extremely linear; it goes: and then ... and then ... and then. A case that merits book-length treatment is one with twists and turns, a progression more complex: ... and then, but ... and then, but ... and meanwhile ...

Stowers tries to overcome this, flashing back and forward and back (and doing that extremely well), but the material, qua story, is just too weak. There is nothing to follow the initial jolt of horror that we get when we realize how young the criminals were and how casually they and all of their chums reacted to word of the murder as the news moved over the Midlothian High School grapevine.

And with the legal shuck-and-jive that followed the arrests, the case -- again, qua story -- falters even more.

Greg Knighten was tried as an adult, found guilty of murder and sentenced to 45 years. The others were offered deals in exchange for their testimony. These were Richard Goeglein, 17, who had been with Knighten at the murder and who, in fact, took Officer Raffield's wallet at the scene. Goeglein, an acknowledged Satan-worshiper who had committed a prior, near-deadly assault, agreed to serve 50 years or a term equivalent to his friend's. His jail time, then, was reduced after Knighten's sentence was announced. Jonathan Jobe, who had, by agreement, picked the boys up after the murder, bargained for 10 years. Cynthia Fedrick, who had helped destroy critical evidence, got even less time.

Then too, there's Greg Knighten mentioning that he'd killed another policeman earlier. Stowers dangles it as reconstructed post-homicide chitchat between Knighten and Goeglein. He raises it again in the latter pages of the book as a recollection by Goeglein, to wit, that Greg " 'found out this policeman over in Duncanville was a narc and talked him into going on some kind of hunting trip. He killed him and hid his body under some brush. He said they never found the guy.' " Then Stowers quotes a quick phone call by the Midlothian police dismissing Knighten's intriguingly detailed claim. " 'They have no record of any missing police officer,' " we hear. And the whole episode, promising a good and much-needed complication, just fizzles.

"Innocence Lost" is, for Stowers, a local story. At the book's start he tells us that he lives a scant 20 minutes from where Raffield's body lay. This, perhaps, accounts for his glowing characterizations of the town officials and police.

It probably accounts too for some of the aspects of the case that Stowers ignores. He never asks, for example, if a few pot busts were worth the risk that Raffield was asked to take.

Nor does he question the way the undercover assignment itself was carried out. This is particularly perplexing, especially since Stowers quotes a Los Angeles police official who rhapsodizes about the Midlothian police department's handling of Raffield's undercover assignment. It seemed inevitable that Raffield would be discovered.

Several students comment about his appearance, from his haircut to his five o'clock shadow. Some referred to him openly as "21 Jump Street." But more than that, Raffield seems to have been inadequately briefed. After he is observed looking at the serial number on Cynthia Fedrick's stolen stereo, for instance, he nonetheless reports it. A day later, the police cinch things by turning up to retrieve the stereo. This hardly seems astute, much less praiseworthy, police procedure.

The reviewer writes frequently about the true-crime genre.