1945: Truck lost at Colmar, France causes theater-wide search
After a great amount of concern, precautionary measures, and an extensive search, the stolen truck and its contents were found in March 1945. The SIGABA and cryptographic materials were recovered intact as they had been locked inside of safes that had not been opened and were dumped into rivers and streams. As it turned out, the investigation concluded that the truck was stolen for the value of the truck itself and the thieves were unaware that the truck contained highly sensitive cryptographic equipment.
Read the NSA publication, "The Colmar Incident" via the link below.