Perlo denied allegations that he had spied for the Soviet Union .
Perlo left government service in 1947 , when his loyalty was called into question during an investigation by the House Unamerican Activities Committee .
Perlo denied allegations that Perlo had spied for the Soviet Union .
Perlo left government service in 1947 , when his loyalty was called into question during an investigation by the House Unamerican Activities Committee .