F-S is right, of course. It's a fictional construct, and doesn't happen like this in real life for all those reasons and a few more. As a former C put it recently, gathering intelligence usually means wanting to keep people alive! But if we don't take it so literally, but instead take it broadly to mean have secret agents killed people in the sort of way we might associate with James Bond, I'd suggest:
USSR - Nikolai Khokhlov springs to mind. A good starting point on that is Soviet Spy Net by EH Cookridge. Henry Chancellor revealed a few years ago that Fleming owned this book and used it as research for From Russia, With Love and a couple of the other novels. Well, did he ever! Chancellor didn't go into too much detail, but if you get the book you'll see that tons of it made it into FRWL, often near-verbatim or just moved around a bit. Grant, Klebb and Ivanova all have elements directly inspired by it, and in the case of Grant all his training is directly from it, and the Khokhlov case in general looms over the novel, and is mentioned by name a few times.
Britain - look at Operation Foxley, which is about as Fleming as you can get. Iideed, it involved Geoffrey Household, from memory.
US - CIA rumoured to use mafiosi, nothing ever proven.
There's a lot more, of course.