BALTIMORE (WJZ) — Millions of dollars worth of historic documents were stolen in a multi-state scam that ended here in Maryland. Now the man behind the historical heist has pleaded guilty.

Andrea Fujii has new details on what stopped the crime spree.

Prosecutors say Barry Landau, 63, plotted this scheme for years. Now WJZ is granted access inside the Maryland Historical Society, where the plot fell apart.

He claims to have one of the largest collections of presidential memorabilia in the world. Now, Barry Landau admits, nearly half of it is stolen. His crime spree ended at the Maryland Historical Society.

“I think they saw that we were a fairly small operation and thought they had a golden opportunity to rob us blind,” said librarian David Angerhofer.

Angerhofer grew suspicious of Landau and his colleague James Savedoff during a July visit.

“They were too schmoozy. They didn’t seem trustworthy,” said Angerhofer.

So he snuck up a back stairwell onto the balcony to get a better look. As Barry Landau distracted the other librarian, he spotted Savedoff steal a document.

“He removed a target folder and placed his own personal papers on top of the document that was inside and removed that into his portfolio,” Angerhofer said.

When police later searched the library locker being used by the two men, they found 60 historical documents stashed inside. Among those were inaugural invitations, a paper from Andrew Jackson and a land grant signed by Abraham Lincoln worth an estimated one million dollars.

“In terms of their value to America, they are priceless,” said Pat Anderson, Maryland Historical Society.

Landau and Savedoff are now accused of library thefts across the Northeast. At times, they hid documents in secret pockets in their jackets. Library officials are just happy history is now back where it belongs.

The Historical Society is now trying to find funding to install security cameras throughout the building.

Landau and Savedoff face a maximum of 15 years behind bars.