BORN TO KILL America's Most Notorious Vietnamese Gang, and the Changing Face of Organized Crime By T.J. English Morrow. 310 pp. $22

"Born to Kill" is crime writer T.J. English's follow-up to his popular first book, "The Westies," a raw account of the Irish mob in New York's Hell's Kitchen. What made "Westies" effective was English's adeptness at weaving first-rate investigative reporting and court testimony (including abundant verbatim recordings of criminal talk) into an absorbing narrative. For that book English had an inside informant, Mickey Featherstone, a vicious gangster who had turned stoolie and who seems to have spent as much time talking to English as he did to his police handlers.

In "Born to Kill" English has used the same formula to portray a notorious Vietnamese gang that carved out a fiefdom in New York's Chinatown during the '80s and early '90s. Here, too, he has marshaled an impressive investigative effort and has made extensive use of police tape recordings. For this story also, English has managed to unearth an inside informant, Tinh "Timmy" Ngo, a Born to Kill gang member who "flipped" and wore a wire during a government task force investigation. It was Ngo's undercover work that allowed Assistant U.S. Attorney Alan Vinegrad to destroy the gang, and it was Ngo's willingness to embrace English as a confidant that lends "Born to Kill" much of its gritty realism.

English tells the story of how an enterprising young Vietnamese gangster named David Thai built a wholesale counterfeit watch business into a thriving criminal enterprise that engaged in extortion, prostitution, commercial robberies and home invasions. Along the way Thai became boss and godfather to a growing number of castoff Vietnamese teenagers, boys who were homeless, alienated and vulnerable to the magnetism of a successful "Big Brother." A refugee himself, Thai had a background not very different from those of the youngsters who fell into his criminal orbit. What distinguished him was his organizational talent and his sure feel for the politics and psychology of Chinatown's Asian underworld.

In late 1987 government racketeering indictments had badly weakened several of Chinatown's established gangs. Sensing an opportunity, Thai gained control of Canal Street, a bustling commercial strip whose shop owners and restaurateurs had long been accustomed to paying protection money to local strongmen. With a firm base in Chinatown, Thai branched out to Asian communities in Brooklyn, the Bronx, Queens, New Jersey and Connecticut. Soon Born to Kill "flying squads" were hitting targets in places as far away as Georgia. Preying exclusively on Asian businesses, Thai benefited from the traditional Asian reluctance to involve American police. For the most part he operated with impunity, relying on his thugs to provide whatever motivation to keep quiet that his victims might have needed beyond the ingrained code of silence.

But not all of Thai's young gangsters had what it takes to become hardened criminals. Some were simply lonely youngsters who adopted Thai as a father and the gang as a family. No doubt more than one's conscience was troubled when they found themselves involved in terror, beatings and murders. Timmy Ngo was one of these. His perspective gives English a standpoint from which to portray the gang's life. It also gives the book the additional dimension of a character study. Ngo seems not to have been motivated by the typical informant's desire to cut a deal with the cops. What he apparently needed was to expiate a burden of guilt. His path to this end was confession, and the many hours he spent talking to English look to be a continuation of the absolution process he began with the police.

"Born to Kill" has its weaknesses. English's forte is crime-writing, not social analysis. An annoying element of the book is its implicit blaming of America's involvement in Vietnam for the sociopathic behavior of Vietnamese criminals in the United States. The trial at which the gang's hierarchy was convicted, English writes, was "a neat, impervious American trial. A trial at which the war in Vietnam was never even mentioned." It's a facile explanation that ignores the brutalization of Vietnamese society that had been going on a hundred years before the Americans arrived. The Vietnamese were cruelly used by the French, the Japanese, then the French again. And before that there were 2,000 years of off-and-on Chinese domination. The Vietnamese themselves, of course, have been great predators throughout their expansionist history and have a rich native tradition of criminal brotherhoods and subversive secret societies. In this context the suggestion of American culpability is superficial and off-putting.

But this is a minor sour note. As a crime story, "Born to Kill" is a revealing, exciting read, a must for anyone interested in the emerging multiethnic face of organized crime in the United States. The reviewer has written five books on Vietnam, including "A Vietcong Memoir" with former National Liberation Front minister of justice Truong Nhu Tang. CAPTION: T.J. English mixes investigative reporting and court testimony in his tale of a Vietnamese gang.