A swastika-emblazoned letter written on Adolf Hitler's personal stationery is now on display inside a glass case at the CIA's secret museum. It was delivered to the museum a day after Navy SEALs killed Osama Bin Laden, NBC News reported. The letter was written by future CIA Director Richard Helms to his 3-year-old son Dennis at the end of World War II. That letter was part of a trove of memorabilia that Dennis sent to the museum 66 years later, in May 2011, to pay tribute to the CIA's roots in a wartime agency called the Office of Strategic Services or OSS. Among the items in the collection Helms sent are a piece of Hitler's personal china and other photos and correspondence. Helms said he found his father's letter in one of his mother's scrapbooks when he was a teenager in the 1950's.