The killing was so improbable it seemed borrowed from fiction. The victim was the author of a best-selling diet book, a wealthy bachelor doctor with a sprawling suburban New York mansion; his alleged slayer was the divorced headmistress of an exclusive Virginia girls' school that numbered among its graduates Katharine Graham, Stockard Channing and generations of senators' daughters. But when Harrison, N.Y. police arrived at the home of Dr. Herman Tarnower last week, they found a scene of violence and tragedy. Tarnower, 69, author of The Complete Scarsdale Medical Diet, lay dying in his bedroom, shot three times. Outside, police intercepted his frequent companion, Jean Struven Harris, 57, headmistress of Madeira School, as she drove away. A .32 caliber Smith & Wesson revolver was found in the glove compartment.

The shooting stunned everyone who knew either Tarnower or his putative killer. "I can't understand it," said a White House source who was friendly with both of them. "Jean was a very strong woman who raised her two sons by herself. She had a deep love for [Tarnower] and she seemed to have a profound desire for him to love her. My understanding is that she may have tried to take her own life first. I'm not sure how she got to that point." Although Harris occupied an official residence on Madeira's Greenway, Va. campus, she commuted regularly to her home in Carmel, N.Y.—about 30 miles from Tarnower's estate. Food critic Craig Claiborne met her at Tarnower's during a dinner party last year. "She was the hostess," he recalls. "She seemed like a rational, charming woman."

Tarnower, too, had admirers. "I'm thinking of throwing a party and inviting all the women who are chasing me," he joked only last year. When asked why he remained a bachelor, he replied, "I'm married to my profession." In fact, his liaisons were frequently gossiped about locally—and there were reports he had become involved with a much younger woman.

Back at Madeira, students and faculty alike said Harris had been under enormous pressure at the 325-student school. Last fall she was forced to discipline several students after a senior society initiation rite in which one girl was accidentally burned with drain cleaner. Only two weeks ago she ordered the expulsion of four girls found using drugs. "Everyone was upset," said one student, "because all the girls were really popular." When the news of the headmistress' arrest was announced, said the girl, there were no tears among the 30-odd students staying at the school over the midterm vacation. "Mrs. Harris was respected by some," she said, "but not really loved."