Even those who love Leicester would not claim, as was once claimed for Liverpool, that it is the center of the universe. A city in the English Midlands, it is in every sense "middling." It has a second division soccer team, a cricket team that never wins the county championship, and a red-brick university whose supreme ordinariness is celebrated in Kingsley Amis' "Lucky Jim."

Leicester, in short, seems a long way off Joseph Wambaugh's normal beat. But, in 1986, the city made history when genetic fingerprinting was used to solve a couple of particularly unpleasant sex murders. "The Blooding" tells the story of the crime and detection that has placed this powerful new weapon in the hands of the forces of law.Wambaugh has two habitual modes of writing: One is black comedy, as in "The Choirboys"; the other is stark reportage, as in "The Onion Field." "The Blooding" is reportage.

After a short - and even rather teasing - prelude, Wambaugh chronicles the facts in his most Sgt. Friday-like manner. In November 1983, a 15-year-old girl was sexually assaulted and murdered. Her violated body was left in a copse alongside a footpath known as "the Black Pad" in Narborough, on the outskirts of Leicester. Leicestershire, a county of 1,000 square miles with a population of about a million, averages one homicide a year. Most of those are domestic and self-solving. Full-blown murder investigations in the English counties are consequently large affairs.

About 150 officers were allocated to the "Narborough murder." Suspicion initially fell on the male population of the three neighboring villages. Semen indicated that the assailant was young and had an exotic blood group. But once the immediate vicinity was screened, police had to confront the awful possibility that their man might live in Leicester (population 300,000) or might be a transient traveling on the nearby M1 highway.

Tabloid interest in the "Village of Fear" was intense. But no leads were forthcoming, and the investigation ground to a halt after six months. Probably the case would never have been solved except that three years later, another 15-year-old girl was raped, murdered and left dead in another Narborough lane. This time the police were quick to round up a plausible suspect - a 17-year-old kitchen porter at the local lunatic asylum.

Although Wambaugh studiously avoids any criticism of the British police, what followed was disturbing. The suspect was puny and at the time of the first rape-murder would have been 14. He was, as one investigating officer candidly put it, "the flipping village idiot." He was cajoled into confessing in lurid detail to the crimes and would certainly have been convicted had the case gone to court. But his father demanded a semen test.

As it happened, at Leicester University, a young scientist, Alec Jeffreys, had recently discovered the technique of genetic fingerprinting. As with digital fingerprinting, no two individuals are the same and the technique is, apparently, infallible. The suspect's sample and those taken from the victim's bodies showed two things; first, that the kitchen porter was innocent. Second, that the same unknown man had murdered both girls. A cynic might also say they showed that the suspect had been very expertly "fitted up" by a police force desperate to get a result.

A shaken murder squad decided to test all 2,000 males in the vicinity. They called it "blooding" - a term that gives Wambaugh his evocative title. The murderer, Colin Pitchfork, turned out to be a local baker with a long history of "flashing" (indecently exposing himself) to young women. Pitchfork easily evaded the blood test by getting an unwitting friend to take it for him. He was eventually caught as the result of information from the public, picked up from casual conversation in a Leicester pub.

Wambaugh, as always, tells a good story. But one cannot read "The Blooding" without some qualms as to what is happening to British law enforcement. As with the "Yorkshire Ripper" investigation, the breakthrough was not the outcome of massive police effort and the mighty apparatus of modern forensic technology. Just as the Ripper case was broken by routine police work (a couple of alert constables on patrol), so the Narborough murder was solved by a public-minded woman communicating her suspicions to a local policeman whom she knew through personal contact. Genetic fingerprinting was primarily useful not in detecting the culprit (who easily evaded it) but in clearing an innocent man whom the police would quite happily have sent up for life.

The police have been Mrs. Thatcher's darlings over the last three Conservative terms. The force's strength has risen to 155,000. They are always first in the pay queue. But the clear-up rate of felonies has, during Thatcher's administration, sunk from 47 percent in 1973 to 32 percent today. In short, there are more police, they are better paid and they solve fewer crimes.

One reason is the force's growing alienation from the community they serve. A local copper living in Narborough would surely have known or have had informants who would tell him of Pitchfork's unsavory proclivities. One can't help feeling that most of Britain's population would happily swap the panda cars, two-way radios, computers, riot-gear and now genetic fingerprinting for the humble bobby on the beat.