Pei-Shen Qian's neighbours in the New York borough of Queens knew he scratched out a living as an artist.
They were less clear on why he kept his windows covered or why, every so often, a man in an expensive car would visit carrying paintings to 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.
Parts of the mystery became clearer as neighbours learned that Qian, a quiet 73-year-old immigrant from China, was suspected of having fooled the art world by creating dozens of works modelled after America's modernist masters and later sold as their handiwork for more than US$80 million.
Qian, who came to the United States more than four decades ago and struggled to sell his own work, earned just a few thousand dollars for each of his imitations.
"He was frustrated because of the language problem, the connection problem," said Zhang Hongtu, a friend and acclaimed artist who lives in New York.
Qian's low profile as a painter evaporated in recent weeks as federal authorities decided that he was the artist whose fakes are at the heart of one of the bolder art frauds in recent memory.
A revised federal indictment handed up this week charged Glafira Rosales, one of the dealers accused of having peddled his works, with money laundering and tax evasion in connection with the sales.
The indictment does not name Qian, but people with knowledge of the case confirmed he was the man referred to in the charges as "The Painter". Neighbours say his home was searched this week by FBI agents.
According to the indictment and other court papers, Qian was discovered selling his art on the streets in the early 1990s by Rosales' boyfriend and business partner, Jose Carlos Bergantinos Diaz, who recruited him to create paintings in the style of celebrated abstract expressionists.
Over 15 years, court papers say, the painter churned out at least 63 drawings and paintings that carried the signatures of artistic giants like Jackson Pollock, Barnett Newman, Robert Motherwell and Richard Diebenkorn. They were not copies of paintings; they were sold as newly discovered works by those artists.
Rosales sold or consigned the art to two elite Manhattan dealers, Knoedler & Co and a former Knoedler employee named Julian Weissman, who in turn sold them for millions of dollars.
Knoedler, its former president Ann Freedman and Weissman repeatedly said they always believed the works to be authentic.
So far, Rosales is the only person to be charged in connection with what prosecutors have described as a long-running fraud. They have not indicated that either art dealer was aware that the works were not genuine.
Zhang was sceptical that his friend could have mimicked the style of such different and well-known artists. His memory of Qian's work was of pastel landscapes and interiors.
"I didn't know he had this kind of good technique," he said. "He had some talent, but I don't believe he can paint in the same style as a Jackson Pollock; it's not easy to copy this kind of style."