A day after the charred body of a prominent Hasidic real estate developer was identified in a smoking trash bin on Long Island, more than a thousand mourners gathered for his funeral in the heart of Hasidic Williamsburg. They grieved for the man they called a pillar of his synagogue and his community, a father of eight who had been quick to donate and quick to lend.

But if Menachem Stark’s name was synonymous with generosity and good deeds within his community, the developer had acquired an unsavory reputation outside it, his business dealings growing in complexity and controversy as he opened new buildings in the hot real estate markets of Williamsburg, Bushwick and Greenpoint.

For all the speculation about his financial situation, it remained unclear on Sunday why Mr. Stark, 39, had been kidnapped from outside his office during Thursday night’s snowstorm and eventually killed. An autopsy found that Mr. Stark died from asphyxiation, indicating that he had probably been suffocated; his other injuries included bruises on his neck and back, and burn marks on his torso and hands, the police said. No arrests had been made by Sunday evening.

From his prosperous-looking brick rowhouse on Rutledge Street in Williamsburg, Mr. Stark had raised a large family and spread his good fortune to his neighbors with an openhandedness that set him apart, friends and community leaders said.