"I was appalled," says Beekman Winthrop, "that such a thing could still happen in the United States in the 1970s." Winthrop, 33, is an earnest, thoughtful former divinity student, Brahmin millionaire and 11th generation descendant of the first governor of the Massachusetts Bay Colony. What appalled him was the murder of Wallace Youmans.

Beekman Winthrop and Wallace Youmans never met, and would have had little to say to each other if they had. Youmans was a poor, unskilled 18-year-old black who was shot down one night in 1970, apparently without motive, as he walked past a white-owned grocery store in the small town of Fairfax, Allendale County, South Carolina. No charges were filed, and the case seemed headed for obscurity until 1972, when a mortally ill former Fairfax constable confessed that he and five other unnamed white men had committed the crime. According to the constable's statement, all six had agreed to kill the first black man who passed by—in apparent retaliation for the wounding of a white man the week before. Despite the "deathbed" confession, state officials unaccountably still failed to take action.

Winthrop read a newspaper story about the case while vacationing with his wife and infant son at their new $100,000 home on the family's Groton plantation in Allendale County. The plantation consists of 25,000 acres, fully one-tenth of the county, and is owned by Winthrop's father Nathaniel and two uncles. Part of the land is rented to tenant farmers, but much is kept as a hunting and vacation preserve. The estate has been in the family since the turn of the century, and "Beek" Winthrop has spent long vacations there since he was a child. Although he lives most of the year in Washington, D.C., Winthrop does not consider himself an outsider in South Carolina.

The newspaper account disturbed Winthrop, and he began to make inquiries. Over the next 18 months he spent some $4,500 of his own money in a lonely and at times monomaniacal quest for justice. The cost in emotional terms was far greater. During his investigation he was threatened, arrested, harassed and often reduced to despair. His nerves frayed, he needed tranquilizers to go to sleep. Yet he persisted because, as he puts it: "The Youmans case was my opportunity to step in and make a difference."

There is little in Beek Winthrop's background to suggest the relentless crusader. Wrapped in purple since the cradle, he earned two degrees at Columbia, studied for the church at Harvard, married a Vassar girl and gravitated to Washington, where he works as a consultant for a nonprofit antipoverty organization called the Center for Community Change, which he also helps support. (The Winthrop family fortune came from banking.)

In his elegant Georgetown house with his wife, baby, three dogs and two cats, Winthrop enjoyed the easygoing life of the well-bred do-gooder. Even in his student days, he did not join any radical groups, nor was there anything of the malcontent in his nature. But if he was not a maker of waves, Winthrop was very much a moralist, and his wealth had made him uneasy. "I have always felt somewhat guilty about my circumstances," he said once. "I felt some obligation to make something of myself."

Once he had committed himself to the Youmans case, it became an obsession. He badgered the U.S. Justice Department and South Carolina officials to reopen the inquiry, interviewed potential witnesses and wrote a 110-page report called "Fatal Shooting of Wallace Youmans, May 16, 1970." Finally, he got results. Citing Winthrop's "sheer persistence," the Justice Department reopened the case in October of last year. Later, and with some reluctance, state agencies also took up the investigation, and in April a South Carolina grand jury indicted five white men for the murder. "I'm not saying that my involvement brought about the indictments," Winthrop says, "but for years there weren't any, and suddenly now there are." Trial is set for later this month.

To the blacks of Allendale County, the shy Winthrop has become a hero. From the start, his wife, sister and father supported his lonely crusade. "My father said he thought that it was my bent," Winthrop says. "He encouraged me to do what was right." But elsewhere in the Winthrop family there is outrage, led principally by his two uncles, Frederick, a country gentleman living outside Boston, and Robert, a retired New York investment broker. "They're caught in an embarrassing position," says Winthrop. "They think it's very inappropriate for me to have become involved. They feel this is a part of the world that hasn't been disturbed and that it is great to have it as old-fashioned and out of the 20th century as it is. They and my father are in a position to enjoy this part of the world on their own terms. That means coming down and shooting birds and vacationing and having people feed them and set their fires—a very quaint, old-fashioned life."

Winthrop is deeply troubled by the rift he has created in his celebrated family. Once, after a severe dressing-down from one of his uncles, Winthrop says he broke down and cried. "In a way," he says, in a moment of self-doubt, "maybe I'm imposing. They are the owners, and maybe it's not my place to get involved."

He has also come to know the discomfort of being a pariah among many of the whites of Allendale County, where he spends some three months each year. Although he says he is not afraid for his safety, he was once warned by a sympathetic policeman that he should "watch out." "I think the people in the community are sort of 'gunning' for me," he says, "and if I make a false move they will try to get back at me in any way they can."