ROCKAWAY, N.J., - When news of a hidden trove of Nazi-looted art in Munich came to light this month, an 87-year-old man in a quiet retirement community in New Jersey straightened a copy of a Rembrandt self-portrait hanging on his wall, completely unsurprised.The picture is a constant reminder to Harry Ettlinger of his days with the "Monuments Men," the allied forces team tasked with returning looted art to its rightful owners at the end of World War Two.The Munich discovery helped reveal a little-known fact about the Monuments Men. Just as their operation was being shut down, they were forced to return some of the recovered art to known Nazi dealers who could document they had owned the pieces before the war.With so much art left unrecovered, and so many pieces not returned to their rightful owners, it was inevitable a hoard of lost works would be unearthed in the future, Ettlinger said."I think this is the beginning," Ettlinger said outside his New Jersey condominium. "It was anticipated by the Monuments Men that I knew that these things were going to come to the surface in the future, and it's happening."The Nazis were instructed by Adolf Hitler to seize art in every territory they occupied. Pieces were confiscated because they were either deemed "degenerate," had been chosen for display in Hitler's museum, or could be sold through the Nazis' art dealers to fund the Third Reich.The Munich collection contained about 1,400 pieces from the apartment of Cornelius Gurlitt, son of known Nazi art dealer Hildebrand Gurlitt. US records show the Monuments Men returned 165 pieces to Gurlitt, though it was unknown whether any more than one of those - a work by German artist Otto Dix - surfaced in Munich. Gurlitt showed papers that he had owned the 165 pieces before the war, said Robert Edsel, author of "The Monuments Men: Allied Heroes, Nazi Thieves, and the Greatest Treasure Hunt in History," the book the upcoming film "The Monuments Men" is based on.Reuters has since discovered archives showing other known Nazi art dealers had work returned to them by the Monuments Men, including Karl Haberstock, who received 29 unnamed paintings, and Maria Almas-Dietrich, who received 22 tapestries.Ettlinger, a German Jew whose family fled to the United States to escape the Nazis, is one of the few surviving Monuments Men who can recall the chaotic process of tracking down and returning millions of pieces of Nazi-confiscated art.With about 350 people working over six years, the assignment was impossible to complete by the time the Monuments Men were called back in 1951, Ettlinger said.Many, including his boss, Senior Monuments officer Lieutenant Commander Jim Rorimer, (played by Matt Damon in the upcoming movie) estimated they were leaving approximately three-quarters of a million pieces of art unaccounted for.Ettlinger said his association with the Monuments Men began in Munich one day in 1945, when, because of his German language skills, he was pulled off a truck headed to the Battle of the Bulge to join the frantic operation."I opened the door and there was a captain," Ettlinger said. "He pointed to a desk and a chair and said, 'This guy at the next desk, he will tell you what to do.' And that was my entry into the Monuments Men." Interrogating men such as Hildebrand Gurlitt to track lost art took time and resources that the group simply lacked, Ettlinger said.Ettlinger interrogated Heinrich Hoffmann, a personal photographer and art collector for Hitler, whose testimony was cagey and impossible to verify, he said."It was not easy," Ettlinger said. "There is no central record in any place where a particular piece of art - and there were literally millions of them - of where the current owner of that particular item is."Documents from the US National Archives verify his claim. In a May 1946 report from the Monuments Men to the US War Department, they asked for more time to continue investigations, saying: "Determination of the scope of the activity of such men as ... Hildebrand Gurlitt ... is vital to the satisfactory resolution of the whole looting problem."Under pressure to return US troops home, the government ordered the Monuments Men to cease operations. Under Military Government Law 59, they were forced to return art to anyone who had documentation."It was the best we could do," Ettlinger said.