Looks pretty innocuous, right? This is part of a letter composed by New York doll shop owner Velvalee Dickinson in May 1942. The FBI decoded it as follows:

I just secured information on an aircraft carrier warship. It had been damaged, that is, torpedoed in the middle. But it is now repaired. … They could not get a mate for this, so a plain ordinary warship is being converted into a second aircraft carrier. …

Probably she was referring to the aircraft carrier U.S.S. Saratoga. Apparently Dickinson had been operating as a Japanese spy throughout the war — her letters to Buenos Aires, ostensibly about doll collecting, had actually contained detailed information about U.S. warships, coastal defenses, and repair operations.

She protested her innocence but got the maximum sentence, 10 years and a $10,000 fine. She died in 1980.