I guess we know that certain governments have engaged in those sorts of killings, but using their own agents.

Although the professional hit man is a staple of detective fiction, no one is really certain if there is someone in this country who makes a living as a hired gun. Organized crime families and drug syndicates have employees who will do whatever their bosses tell them to do, which often includes firing machine guns at certain rivals or burying them in cement. And there are the occasional wannabe mercenaries who take out ads in the backs of military magazines claiming that they will do anything asked of them. But they almost always turn out to be frauds. If there are highly qualified triggermen making their talents available to ordinary citizens, says Johnson, “then they don’t advertise very well. They certainly aren’t advertising in Houston. I’ve never heard of such a person.”