NAPLES, Italy -- For months now, the alarm has been resounding throughout the insular and competitive world of antiquarian books: beware of volumes bearing the stamp of the storied Girolamini Library in Naples. They could be hot.
The library's former director, Marino Massimo De Caro, was arrested in May, accused of systematically despoiling the library he had been charged with keeping safe, stealing books and selling them on the open market or directly to collectors. And sharp sleuthing on the part of a professor at Georgia State University in Atlanta has raised questions about Mr. De Caro and the sale of other, possibly forged, books.
The unraveling of Mr. De Caro was precipitated by a chance visit to the library in March by Tomaso Montanari, a professor of art history at the University of Naples and a regular contributor to the daily newspaper Il Fatto Quotidiano. What he saw there -- books piled haphazardly throughout and empty shelves, soda cans and garbage strewed about -- immediately went into print, and that prompted a petition signed by hundreds of Italian intellectuals questioning Mr. De Caro's appointment as director.
More important, Italian prosecutors took note and weeks later Mr. De Caro was in prison, accused of -- but not yet formally charged with -- embezzlement and conspiracy. Prosecutors say that in the 11 months during which he managed the library, Mr. De Caro stole hundreds of its volumes. Investigators found boxes of valuable books, many with the library's stamp, in garages and private homes in several cities as well as in auction houses abroad. Four people said to have conspired with Mr. De Caro were also jailed.
"So far, we've tracked down some 3,000 books," including some blocked at auction, said Giovanni Melillo, the Naples prosecutor handling the Girolamini investigation, in an interview. He said that Mr. De Caro was the head of a criminal gang created to despoil the library, which had been off limits to the public -- with few exceptions -- for decades. "There was a lucidly conceived plan behind it all," Mr. Melillo said.
Prosecutors say that Mr. De Caro has admitted to taking some books with the intent to sell them, but solely to pay for the restoration of the underfinanced library and its precious volumes. Mr. De Caro's lawyers declined to comment while investigators were still at work.
The question of how Mr. De Caro ever became the director of such a renowned library sheds light on some of the entrenched practices that continue to bedevil the Italian economy.
In April 2011, Giancarlo Galan, then the culture minister, named Mr. De Caro as his special consultant, and he was reappointed in December by the current minister, Lorenzo Ornaghi. In June 2011, the Culture Ministry ratified his appointment to the library.
"It was like putting a fox in a chicken coop," Mr. Melillo said dryly.
Mr. De Caro may not have had a degree in library sciences, but he had other credentials. "De Caro is the quintessential Italian fixer. In a country where the political class still controls a significant part of the national economy, he connects politics with business, and vice versa," said Claudio Gatti, a co-author of a new book, "Il Sottobosco" ("The Underworld").
"People like him exist all over the world, but here we have a twist," Mr. Gatti wrote. Mr. De Caro "can count on relationships with both the right and the left."
"Only in Italy can you have someone like him," he concluded.
One serious problem facing investigators here is that they do not know the exact number of books that may have been stolen. Only half of the 170,000 or so books in the collection were ever cataloged, according to Mauro Giancaspro, the director of the National Library of Naples.
After Mr. De Caro took over last summer he began to move books from their shelves and between rooms, to preserve the books and rid the shelves of wood worms, he told investigators. Instead, prosecutors believe, the books were rearranged and index cards were destroyed to make it difficult to track missing volumes.
The investigation, Mr. Melillo said recently, has taken an "international bent," and his team is following new leads.
Mr. De Caro, whose résumé boasts a colorful employment history, had at least one academic credential under his belt: he had published a two-volume study of Galileo. That is one connection to the Georgia State professor, Nick Wilding, a Galileo expert who is currently investigating the authenticity of several books by the Pisan astronomer.
One in particular, a copy of "Sidereus Nuncius," Galileo's novel observations of the cosmos first published in Venice in 1610 and now owned by a New York rare-book dealer, is clearly a forgery, Mr. Wilding says.
The book in question -- supposedly containing an inscription by Galileo, along with five of his watercolors -- was presented with much fanfare (and some doubts about its authenticity) in Padua five years ago. A two-volume study published last year concluded that it was Galileo's autographed proof copy.
"It all seemed very convincing," Mr. Wilding said. "The paper appeared genuine, the binding seemed convincing." But there were "minor details that made me question the entire account," he said in a phone interview. He decided to look more carefully at the book.
The breakthrough came when he discovered photographs of a copy of "Sidereus Nuncius" published in a 2005 catalog from Sotheby's. Looking at the photograph of the title page, he noticed that what should have been random ink blots were identical to deeply impressed marks in the New York "Sidereus Nuncius."
In addition, one letter in both copies had the same blotch on its foot. This blotch was not in any genuine copy, but was to be found in a facsimile edition published in 1964. The facsimile used a copy that had a brown mark on the paper next to the letter. The black-and-white photograph transformed it into a printed blotch, proving to Mr. Wilding that the New York and Sotheby's copies were both forgeries based on the 1964 facsimile.
"If they hadn't been greedy enough to make two copies, I wouldn't have been able to prove the forgery," he said.
The quality of the books, in any case, has amazed the experts.
"We've seen missing pages replaced in facsimile, but no one dreamed that an entire book could be forged, something that is now more easily possible because of modern technology," said Owen Gingerich, professor emeritus of astronomy and the history of science at Harvard and a senior astronomer emeritus at the Smithsonian Astrophysical Observatory.
Mr. De Caro, Mr. Gingerich said, brought the "Sidereus Nuncius" with the forged watercolors to his office in 2005, when he was trying to sell the book. "I told him that the watercolors could not have been made by Galileo because of an astronomical blunder in one of the drawings," he said.
Mr. Gingerich and Frank Mowery, of the Folger Library, have detected what Mr. Gingerich said were other forged titles, including three copies of another Galileo book, "Le Operazioni del Compasso Geometrico e Militare," from 1606. At least one of these passed through Mr. De Caro's hands, Mr. Gingerich said.
"I don't know if he commissioned them, or manufactured them, bought them repeatedly or was just unlucky," Mr. Wilding said of Mr. De Caro. "I am worried that these are not the only ones in circulation."
Arnoud Gerits, president of the International League of Antiquarian Booksellers, recently issued a statement warning members about the theft of books from the Girolamini Library, along with Mr. Wilding's findings of what he has called forged Galileo materials that "appear to trace back" to Mr. De Caro. "It seems clear that this is a major case of both theft and forgeries of important material," the statement read.
"Dealers don't want to blow the whistle," said Mr. Wilding, who nonetheless welcomed the association's alerts. "But one dealer also quipped that any rare book that's worth selling has been stolen at least once in its life, hopefully not recently."
This article originally appeared in The New York Times.