A direct confession of atrocity is less credible than a denial

Evidence

I cannot explain it. I do not know why students would take the word of a minor official who says nothing bad took place over that of a commander who confessed to operating a mass murder machine. If you were serving on a grand jury investigating a murder, which would you find more credible: the testimony of the driver of a get-away car who swears he saw nothing bad happen or the detailed confession of the person who says he pulled the trigger? — Bob Altemeyer, The Authoritarian Specter, 3194