The FP-45 Liberator was an inexpensive pistol designed by the U.S. military during World War 2 to serve as a disposable one shot pistol. Though described as an 'assassination weapon' some historians bristled at the connotation, indicating that the intent was to provide ultra cheap weapons which could be dropped behind enemy lines to friendly forces and used in a self defense capacity. The simple design and single shot capacity would ensure that the weapon be regarded as relatively useless by any enemy military, but could be used as a last ditch defensive weapon or one used to procure more weapons from occupation forces. Most of the Liberator pistols manufactured were never distributed and were destroyed after the war. So far there is no documented evidence of their usage as a weapon during WW2.
The FP-45 Liberator can be seen in the following video games used by the following actors:
