But imagine this, there were two people involved, or one is involved, and the other one knows, and is the weak link? He has no prior criminal history and is somewhat naive.. He feels shame, guilt, whatnot. But the other one, who is smarter, and more criminally experienced, calmly explains that LE has nothing on them, that it is a totally cold case, "unless you open your stinking mouth", and then he explains what the other one might get. And the other one is silent, but he can still talk. (I sometimes wonder that "the change" DC spoke about is simple depression, not change in looks or situation.)
In this case, this weak link might need to be reassured, because he has been brainwashed by the true killer, and was explained that if he sings, he'd be a fool?