In early December 2014, just as he was allegedly embarking on a scam to bilk his friends and family out of at least $95 million, Andrew Caspersen, then 37, participated in a “networking” event at the Princeton Club, on West 43rd Street in Manhattan. Given by and for alumni of the exclusive Groton School, northwest of Boston, the event, titled, without irony, “From Schoolroom to Boardroom,” was a typical gathering for the East Coast elite to slap backs, make connections, and further already prosperous careers—skills that Andrew had honed to a fault over the years.

That evening Andrew radiated prosperity and achievement. A managing principal at the Park Hill Group, in New York, he was dressed in a dark pin-striped suit, starched white shirt, and yellow rep tie. As some in the audience recalled, he was quiet, a bit arrogant, but approachable and happy to talk about his own success. “He was prototypical of what you, by your senior year, would want to become,” says one Groton graduate who was there that night. “He just kind of had everything.”

Andrew’s job at Park Hill—then a division of the Blackstone Group, the global financial behemoth—was to advise investors and private-equity firms on the arcane art of buying and selling limited-partnership interests in other private-equity firms. His was a specialized skill, which he had learned as a corporate lawyer on Wall Street and then as a partner for eight years in the New York office of Coller Capital, a London-based asset-management firm that specializes in buying such limited-partnership interests. At Park Hill, Andrew was being paid handsomely for this work: $3.68 million in 2015 and $4.5 million in 2014, according to federal prosecutors. “He was that symbol of the guy who worked at a law firm and then figured it out and translated that into a private-equity firm and then became a partner at another firm,” says Stephanie Borynack Clark, Groton class of 1992 and the proprietor of the Wally Findlay Galleries, in New York.

Fifteen months later the purported charade was over. On Saturday, March 26, at 5:30 P.M., at New York’s La Guardia Airport, federal agents arrested Andrew in front of his wife and two young children. He was charged with one count of criminal securities fraud and one count of criminal wire fraud. The family was returning from a vacation in the wealthy enclave of Jupiter Island, Florida, where Andrew’s 71-year-old mother now lives full-time and is a doyenne of the social scene. According to The Wall Street Journal, upon his arrest Andrew said little and surrendered quickly. His wife, Christina Frank Caspersen, the director of global investor relations at Anheuser-Busch InBev, “appeared to be in a state of shock as her husband was escorted away,” the paper reported.

She was not the only one. As news of Andrew’s arrest spread throughout the financial world, there was utter disbelief. On Jupiter Island, it went down hard. His mother is a “beloved figure” there, according to Nathaniel Reed, whose family developed this spit of land in southeastern Florida, now home to the likes of Tiger Woods and Dick Fuld, the disgraced former Lehman Brothers C.E.O. “Old Wall Street in shorts” is how Fred Whittemore, a former longtime partner at Morgan Stanley and a business partner of Andrew’s late father, Finn Caspersen, once described the island. “[It’s] tragic for her and the rest of her family,” Reed says. “Her grandchildren have all been here for spring vacation, and they are the most delightful people . . . So you can imagine this has had a colossal impact on her. But she’s showing her usual bravery.”

People who know Andrew were desperately trying to understand what could have possessed someone who seemingly had it all to allegedly cross so many boundaries into immoral and criminal behavior: after all, not only is he charged with stealing millions of dollars but he supposedly took it from his close friends and family—including his mother—by constructing an elaborate scheme using the tradecraft he had learned on Wall Street. It depended on a desperate confidence game, in which he supposedly exploited his victims’ refusal to believe that someone of his pedigree and education, someone who was part of the Club, would betray them.