PHILADELPHIA (CBS) – Could an accused historical document thief have tapped a Philadelphia trove?  The Historical Society of Pennsylvania is combing through hundreds of boxes in its collection to make sure nothing is missing.

The search began after a presidential historian who used the Philadelphia-based collection was charged with stealing documents from the Maryland Historical Society.

READ MORE: Gas Prices Continue To Fall In New Jersey, Pennsylvania And Delaware

The Historical Society of Pennsylvania, at 13th and Locust Streets in center city, is closed on Mondays. That makes it a good day, says president Kim Sajet, to go through the boxes that had been handled by historian Barry Landau, 63, and his co-defendant, Jason Savedoff, 24.

“They did request a lot of material,” notes Sajet. “You know, it takes a good eye and some patience to go through this very systematically, but we are going to devote all of today to that.  And we’ll keep going until we’ve done everything.”

Sajet says Landau and Savedoff visited the HSP collection a total of 17 times and, toward the end, the staff was getting suspicious.

With a bit of what Sajet considers chutzpah, Landau presented the library with a copy of his book, The President’s Table; when they wrote to thank him, the card came back marked “addressee unknown.”

READ MORE: Many Families Expected To Travel To Jersey Shore For July 4: 'I Gave Up Other Things Just To Make It To Ocean City'

And Savedoff, she says, used an alias and a phone number that they later learned didn’t belong to him.

She says after the staff started questioning the pair, they stopped coming in.

“We have a pretty rigorous security process here,” Sajet told KYW Newsradio today.

Landau and Savedoff are being held without bail after authorities caught them taking valuable documents from a collection in Baltimore.

Reported by Pat Loeb, KYW Newsradio 1060

MORE NEWS: Investigation Underway After 2-Alarm Fire Leaves Man Dead, 2 Firefighters Injured