Sean B. Fegan eventually gave up on the lettuce he planted in his family's garden in Blauvelt in Rockland County, where he visited for Sunday dinner every week. "His scallions were his biggest success," Mr. Fegan's sister Anne Marie said; the lettuce was one of his rare defeats.

At 34, Mr. Fegan was a senior equity trader and an assistant vice president at Fred Alger Management Inc. He was meticulous about the way he looked. "He ran and worked out," Ms. Fegan said. "He had really beautiful blue eyes." Mr. Fegan also had to get the details right, whether in long, funny stories he loved to tell or when quizzing his parents, Colette and Peter, and Anne Marie and his other siblings, Catherine and Peter Jr., about how their lives were going.

But Mr. Fegan also liked to party in Manhattan, where he lived, to go to Jets games and to travel to Europe, often with his girlfriend, Jenny Hebeler. A favorite destination was County Cavan in Ireland, where his family came from and still maintains a home. He wanted the family to have dual citizenship and had applied for it for himself. "He was very proud of his heritage," Ms. Fegan said. "He always made the most of life."

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