Adolf Hitler, Pol Pot, Slobodan Milosevic. They are household names, infamous for masterminding genocide. But who were the foot soldiers who did the dirty work?

In many cases they were equally notorious in their communities because they were the friends, neighbors and co-workers of those they raped, slaughtered and buried alive....

Researchers say most perpetrators of genocide were not destined for murder and had never killed before.

"You don't have to be mentally ill or even innately evil or criminal. You can be ordinary, no better or worse than you or me, and commit killing or genocide," said Harvard psychiatrist Robert Lifton, who has studied Nazi doctors.

"The truth is that we all have the possibility for genocidal behavior."

Experts have reached a troubling conclusion: It was actually very easy for the architects of genocide to find more than enough ordinary people to do the killing.