Conger, the protagonist, is given a chance to get out of jail if he agrees to travel back in time and kill a man. He has agreed to kill a stranger he has never seen. He isn't concerned about getting the wrong man. He knows what the man looked like. There was no way he could make a mistake about his target's identity -- he has the man's skull under his shoulder.
The Sword of the South
Leviathan
Catholic Guilt and the Joy of Hating Men
Star Trek: New Frontier®: Blind Man’s Bluff
The Dragons of Dorcastle
The Price of Freedom
The Ultroom Error
Tangled Up in Blue