|From The Fall of Fortresses by Elmer Bendiner|
Now it gets interesting. The shells had been sent to the armorers to be defused. The armorers told him that Intelligence had picked them up. They could not say why at the time, but Bohn eventually sought out the answer. Apparently when the armorers opened each of those shells, they found no explosive charge. They were as clean as a whistle and just as harmless.
Empty? Not all of them! One contained a carefully rolled piece of paper. On it was a scrawl in Czech. Translated, the note read:
"This is all we can do for you now..."
Using Jewish slave labor is never a good idea. Via Posthip Scott. Paraphrased by me.