Christian Popescu of Kenmore pleaded guilty Thursday, March 12 to charges of trying to sell a stolen bookmark that is thought to have belonged to Adolf Hitler.

The man admitted to trying to sell the item for $100,000 to a U.S. Immigration and Customs Enforcement agent at a Bellevue Starbucks.

The bookmark was taken from a Spanish auction house in 2002, according to the U.S. Attorney’s Office.

The bookmark is thought to have been a gift to Hitler from his mistress Eva Braun after the Russian army defeated the Germans at Stalingrad in 1943.

Popescu faces up to six months in jail under the terms of a plea agreement.