There was no sign on the former brick factory on the treeless block in Red Hook, Brooklyn, where Arthur Mondella worked. No name on the door. Nothing — other than the bright-red liquid trickling onto the sidewalk and into the gutter, and the thick scent of syrup on a summer’s day — to announce the presence of one of the country’s largest suppliers of maraschino cherries.

“Look at this building,” said Brian Connell, 68, who has lived next door to Dell’s Maraschino Cherries for nearly 20 years. “It’s totally anonymous. And then, here you see this Porsche Carrera being backed out. I say to myself, ‘The cherry business is profitable! Who knew?’ ”

Mr. Mondella’s company, which his grandfather and father founded in 1948, was indeed large and, to all appearances, profitable. But the Dikeman Street plant had some trappings the neighbors found curious. The fleet of vehicles Mr. Mondella kept in the garage, for instance, including the Porsche, a Rolls-Royce, a Harley-Davidson and a Mercedes — all pure white. The security cameras bristling from the building’s corners. The razor wire barricading its roof.

On Tuesday, Mr. Mondella, 57, shot and killed himself in his office bathroom just as city investigators were discovering that a marijuana farm lay beneath the factory. On Wednesday, investigators were still sorting through what was legal and what was not at the plant. According to one law enforcement official, who asked not to be named because he was not authorized to comment on a continuing investigation, it appeared that Mr. Mondella’s employees had not known about his other operations.