All I can say was this was an almighty cock-up by both American security services for not vetting properly, and Winston Churchill for stopping Verona (the monitoring of Soviet traffic from their London embassy, which would later prove the Rosenbergs were spies! Many years after their execution, but it is reassuring to know you got the right people

They were the first US civilians to be executed for espionage.
Amazing how their actions helped to precipitate the Cold War and the arms race, and yet resulted in the collapse of the v.thing they supported (communism)!
Life is a funny old thing ain't it?
Ozzy