Mr. Khan, 51, comes from a prominent family in Pakistan — relatives said he was a favorite nephew of Bashir Ahmad Bilour, a well-known politician who spoke out against the Taliban. Mr. Bilour was killed in a suicide attack in late December. Trained as a doctor, Mr. Khan came to the United States in the 1980s, but ended up working with his sister and her husband, who owned some two dozen delis across Staten Island. From there, Mr. Khan set out on his own, building up Richmond Wholesale Company, a cigarette and grocery business that recorded $125 million in sales last year, according to Dun & Bradstreet, a financial information provider. Richmond Wholesale supplies products to delis and gas stations across the New York region. Mr. Khan also owns three delis. Mr. Khan, until recently the chairman of the board of a prominent Staten Island mosque, was known in the borough’s close-knit Pakistani community as a flashy businessman. He was also a generous supporter of politicians of both major parties, giving more than $65,000 to more than 40 campaigns in the last decade.