This sounds suspiciously like the cannibalism myths found throughout history, where one race/tribe/group demonized their opponents by telling stories of horrible atrocities. Similar to the more modern "premature babies removed from incubators and left to die" story that was told about Iraqi troops in Kuwait (and which subsequently turned out to be a lie).

The problem with this type of scheme would be that sooner or later, one or more of the executioners are going to figure out what's going on. There was a movie starring Pierce Brosnan as a KGB agent who was assigned to set off an atomic bomb in the heart of England (presumably to look like a terrorist attack). On several occasions, he received orders - which he dutifully carried out - to kill the person he had been working with to prevent them from talking afterwards. But of course, being no dummy, he clued in at the end that, if they were killing off everyone who knew about the scheme - and he knew about the scheme - then there really wasn't likely to be a ten-minute delay on the bomb trigger to allow him to escape.

Somehow, I think letting a sociopathic, highly-trained killer know that you were planning to double-cross and murder him would backfire more often than not <img src="/images/graemlins/crazy.gif" alt="" />

(Of course, I *have* to say that <img src="/images/graemlins/wink.gif" alt="" /> )