I still get chills thinking about watching that when it aired. The weird burping and grunting and then the audio of him clearly staring at his reflection in the mirror. With the hot mic still going, he laid it all out there. *shudder*
According to the Wikipedia, the audio in the documentary was actually edited, shuffled, and played out of sequence. Not that there's any doubt about his guilt of course.
I’m sure it was but I don’t know that you could make an argument against the ambiguity of “well, they got you. You’re caught.” And “what did I do? Killed them all, of course.” Those two things could come anywhere in between the rest and still be damning.
Possibly one of the greatest TV moments, I was on the fence the whole series on whether this guy just had bad luck, and then he just laid it all out and the hot mic caught it, my wife and I were like "no fucking way!!" when it happened.