When a well-known dealer of rare maps was caught stealing from a Yale University library in 2006, a FBI investigation ensued that revealed the man had stolen millions of dollars worth of antique maps and other items from institutions around the world. Most of the pilfered material was eventually returned to its rightful owners, but many items remain unclaimed.

The FBI has retained 28 rare maps and books—some dating to the 17th century—and would like to return them to their rightful owners. An online photo gallery and information about the items has been posted so that individuals or institutions who are missing items can browse the finds.

“These items have been legally forfeited to the U.S. government,” said Bonnie Magness-Gardiner, who manages the FBI’s Art Theft Program. “Technically, they belong to the Bureau now, but we don’t want to keep them. Even though we have tried to find the rightful owners over the years, we are making another attempt.”

Edward Forbes Smiley, III was arrested for the Yale library theft, and he admitted to stealing and selling nearly 100 rare maps from international collections over a period of seven years. With Smiley’s cooperation, the FBI tracked down most of the dealers and collectors who purchased the approximately $3 million worth of stolen material. But returning the maps to their homes proved to be a daunting task.

In many cases, the maps were cut from books with a razor and trimmed so they didn’t look like they came from books. Some of the maps had different titles—many in Latin—and could have come from several known copies of the same book. To further complicate matters, many libraries weren’t even aware they were missing items until contacted by the FBI.

“These maps aren’t vehicles with identification numbers stamped on them,” Special Agent Stephen J. Kelleher, who led the 2006 investigation, said at the time. Special Agent Lisa MacNamara, who is working the case now from the New Haven, Connecticut Division, added, “Our hope is that by reaching out to the public in this way, we can get these historical items back to where they belong.”

Among the items still in possession of the FBI are rare maps such as an 18th century depiction of the United States, a 1683 street plan of Philadelphia, and several antique books.

View the photo gallery here and parties who are missing any of the pieces shown should contact Special Agent MacNamara at (203) 503-5268, or send an e-mail to artwork@ic.fbi.gov.