Four weeks ago Anthony Melnikas, art history professor at Ohio State University, brought a plastic envelope to Bruce Ferrini, a rare book dealer in Akron, Ohio. Inside were two illuminated parchment pages, one of them depicting a man threshing grain which Mr Ferrini described as among the very finest specimens in existence - so fine indeed that he was instantly suspicious of their origin.
A check with an art historian friend at Princeton University provided Mr Ferrini his answer. The pages belonged to a book compiled by scribes around 1300, containing texts about farm and monastic life and military theory in the early Roman Empire. The volume had been owned and personally annotated by the great 14th-century Italian poet Petrarch, before passing to the Vatican. Their estimated value is $500,000.
Mr Ferrini notified the United States Customs, and US Customs the library in Rome, where a check on the manuscript, catalogued simply as Vaticani Latini 2913, confirmed every fear. Three pages, including the two offered by Professor Melnikas, had been chopped out of the thick leather bound volume, apparently with a penknife. Records showed that the professor had studied the manuscript on 27 July, 1987. Since then 10 other scholars had access to it, but either did not notice, or gave no attention to, any missing pages.
So precious was the manuscript that it was available to only a handful of the most eminent researchers - among them the 68-year-old, Lithuanian- born professor, author of what many say is a definitive study of 12th to 14th-century manuscripts, and who discovered in 1990 an unpublished map of the New World by Leonardo da Vinci, dating to the 16th century.
Now disgrace threatens to overtake his long-planned retirement after 35 years on the Ohio faculty. Professor Melnikas has been questioned by US investigators, but has thus far not been charged with any offence, either in the US where smuggling can be punished by up to five years imprisonment, or by the Vatican.
The professor admits the manuscript pages were in his possession. But he denies having stolen them, or that he planned to sell them.
But Mr Ferrini claims to have proof that at their 4 May meeting, Professor Melnikas asked him to try and complete the sale by 30 June, the day before his retirement, telling him he wished to use the proceeds to fund scholarships for the study of medieval manuscripts.
Whatever the truth, the affair is a scandal American scholarship, jarred by several lesser such incidents in recent years, would far rather be without.