They don't kill random people when they are following you. I discovered something similar to yours, Crimson.
What I did was brought some bandits to Oakvale and then proceeded to tell them to wait there. Out of nowhere, one of bandits struck down and killed a passing woman and then proceeded to go after the Guards. Apparently, they are still scripted to attack the villagers and other characters that are not the Hero
.
Happy pillaging.