Complex sentence: One of his subordinates created a fake diary describing the use of the factory, which would have been planted in the corpse of German soldier, to be "found" as proof of the story, but this plan was eventually dropped.
Split into simpler sentences: One of his subordinates created a fake diary describing the use of the factory. This was to have been planted on the corpse of German soldier, to be "found" as proof of the story, but this plan was eventually dropped.