Pei-Shen Qian’s neighbors on 95th Street in Woodhaven, Queens, knew he scratched out a living as an artist: he often dried his paintings in the sun, propping them up on the weathered white siding of his modest house.

They were less clear on why he kept his windows covered, or why every so often a man in an expensive car would come to the house carrying paintings to, not from, a painter.

“He would bring a painting in and show it to him, for him to work on or fix up something,” Edwin Gardiner, 68, who lives across the street, said before pausing and adding, “I don’t know what he did with it.”

Parts of the mystery became clearer on Friday as neighbors learned that Mr. Qian, a quiet 73-year-old immigrant from China in a paint-flecked smock, is suspected of having fooled the art world by creating dozens of works that were modeled after America’s Modernist masters and were later sold as their handiwork for more than $80 million.