Throckmorton says he knows of one man who had bought many Hofmann documents, planning to sell them to fund his retirement. He knows now they're fakes but continues to sell them on eBay, Throckmorton says.

Ashworth remembers seeing a Hofmann Paul Revere letter at a Las Vegas auction house in 1997. He warned the dealer, who said it had been "checked out by our experts." It sold for $31,000. Then there was the famous Emily Dickinson poem — not only forged by Hofmann but written by Hofmann as well. Ashworth told Sotheby's auction house it was a fake, but the dealer still sold it to a Massachusetts museum, which later discovered that Ashworth was right.

Was he the best forger — or at least the best forger who was caught — in the past 1,200 years?

That's what the Southwestern Association of Forensic Document Examiners voted a few years ago. They have a grudging respect not only for the skill of Hofmann's handwriting — no stops and starts, no tell-tale angles — but by the breadth of his work.

While most forgers specialize in, say, Abraham Lincoln, Hofmann could do 86 signatures. He made his own ink, created his coins and currency, fashioned his own postmarks.

"He had his documents authenticated by the best: the Library of Congress, the American Antiquarian Society, the FBI, the University of California, the McCrone Research Institute," said Throckmorton, who prides himself on being the examiner, along with Bill Flynn of Arizona, who uncovered Hofmann's secrets.

Book dealer Jennifer Larson, though, doesn't give Hofmann such high marks. Lots of other forgers are better at ink, paper, calligraphy, history, aesthetics, she says. What Hofmann excelled at though was "an ability to select and exploit his victims with a heartless eye towards their particular weaknesses, and a total indifference to the damage that he was doing to them, and to trust among human beings in general," she said. "I think this is a psychiatric characteristic that he can't help and merits no accolade."

In the end, of course, Hofmann did get caught — because of the murders, but also because of his mistakes. What the examiners noticed first, after putting his documents under ultraviolet light, was a "blue hazing effect" and ink that ran in one direction. Under the microscope they noticed that the ink was cracked. But to prove forgery they had to be able to duplicate these subtle mistakes.