Too bad that they don’t execute spies anymore... They should. That would be a reasonable deterient.
Since they stopped executing them the money is just too enticing for these low paid civil servants. Think of it... You’re investigating billionaires but being paid a hundred thousand and less to do it. A bag full of nontaxable cash is difficult to refuse... Unless you’re facing death. Then it becomes more difficult.
Aldrich also became a committed communist, after the money enticed him.