Bad Karma : A TRUE STORY OF OBSESSION AND MURDER by Deborah Blum (Atheneum: $17.95; 320 pp., illustrated)

Tragic events do not usually announce themselves. But often, in retrospect and sometimes with painful clarity, we are able to see the tragedy as a result not of destiny but of our own blindness, inaction or apathy. It is as true for space shuttle disasters--where we learned, too late to save seven lives, what technicians knew about O-ring defects before launch--as it is for murders.

Especially for murders. And especially when the killer knows the victim and the victim knows the killer.

Almost 17 years ago, Tanya Tarasoff, a 20-year-old Berkeley coed, died on the front lawn of her parents’ middle-class home, eight brutal stab wounds in her chest, abdomen and back. Tanya had met her killer, Prosenjit Poddar, a 24-year-old graduate student from India, a year earlier. They had danced together, spent hours talking together, shared with friends their feelings toward one another. So what happened? Didn’t anyone know about the O-ring defects in their characters?

The answer, as Deborah Blum makes abundantly and unflinchingly clear in “Bad Karma,” is Yes.

But if there is anything that Blum captures with near-flawless focus in this, her first book, it is the inexorable path toward Tanya’s death. What makes this story of “passion, obsession and madness,” as the subtitle aptly describes it, so compelling is not our impatience to know “ who done it,” or even why . We are drawn relentlessly into this tale of two young people--a man obsessed with a woman who refuses to release him--because, from the beginning, we sense that Tanya and Prosenjit’s relationship is a folie a deux ; and we are just as relentlessly hoping that, somehow, someone will put a stop to the madness before it’s too late.

We keep reading, keep hoping.

But in this bizarre story, there are only fleeting reasons for hope. From their first meeting, at a folk dance at Berkeley’s International House in the fall of 1968, to their last angry encounters in the fall of 1969, these two innocents play an increasingly dangerous cat-and-mouse game.

Prosenjit, a brilliant but painfully shy mechanical engineering student, one of only a few Indian Untouchables to ever earn the right to study abroad, had “never so much as shared an intimate moment with a girl, let alone a romance,” when he first sighted Tanya’s “raven-haired, green-eyed lissomeness.” The first symptoms of his pathetic delusions surface immediately. After his first forlorn date with the American girl, he writes home, telling his parents that “quite naturally, the family looks to me to express my intentions” about marriage. Blind to everything but his own intoxication, Prosenjit began massaging his fantasies early.

But Tanya, who “felt an enormous vacancy at the center of her life that only the right man could fill,” did little to disabuse the Indian of his wild dreams. While “wishing he’d disappear off the face of the earth,” Tanya would feed Prosenjit’s obsession with occasional “wet kisses.” “There was something about taunting him that she seemed to enjoy,” Blum writes. She toyed with the meek and reclusive Prosenjit to the very end.

The tragic irony was that “the Little Hindu” knew what she was doing. Rather than fleeing, however, with the steel-trap logic of madness, Prosenjit built a sophisticated taping system in his dorm room. He decided to record their conversations in order to have “concrete and indisputable proof that she loved him.” Instead, as was Prosenjit’s fate, in the first conversation, Tanya tells him about “this guy I really cared about.”

Bad karma, indeed. But it was known to more than the gods. Tanya’s best friend, Cindy, warned her not to make light of the “marriage sari” Prosenjit had given her. (Instead, Tanya tells him she will burn it.) And two months before she was killed, Prosenjit’s therapist at the University’s psychiatric clinic warned a colleague that Tanya “may be setting up her own execution.” (The psychiatrist tried, unsuccessfully, to commit him to a hospital and was put on probation for his efforts.)

The good news about “Bad Karma” is that Deborah Blum is an utterly engaging and provocative storyteller. The book mesmerizes us with its waves of lush detail.

One question, however, is whether we aren’t pulled too expertly to the edge of our seats. Blum, a Los Angeles film producer, admits that “it often became necessary to reconstruct dialogue and occasionally to create scenes.” And though we want to believe that “this ‘dramatic license’ (was not) taken in such a way as to distort actual events,” we can’t help but wonder how a created scene will not be a distortion. Blum also admits to another bad habit for a serious nonfiction writer: the creation of “composite characters.” Is this cavalier (at least she confesses) paddling into the murky waters of “fascination” a mortal sin? The jury is still out.

But until there is a verdict, “Bad Karma” must stand as a masterful re-creation of one of the most tragic of avoidable events, full of insight into obsession, madness and murder.