IMO, I believe he used the "N" word. I think LE threw the "half-breed" terminology out to the media in an attempt to throw the SK off his game, in hopes to lure him out somehow.
It backfired though, obviously and now that term has just stuck over the years. It makes LE appear untrustworthy if they try to correct it at after the fact, so that may also be why they are withholding the tapes, if there are any tapes at all.
I don't buy the false confession excuse. There are plenty of other ways to weed out false confessions. For example; if the voice on the tape doesn't match the person confessing to the crime, then most likely they aren't the killer. (Duh!)
MB was the first of the GB4 victims and IMO he simply enjoyed the idea of taunting the family, so he called. He probably assumed LE wasn't going to use time & resources in Buffalo, given her profession and the fact that her residence / last know whereabouts was in the Bronx, almost 8 hours away. And...certainly not to the extent of recording calls, then being on standby and trying to trace them as they came in, when there was no guarantee that he would even call again.
I believe that he ultimately got wind that he was 'potentially' being recorded, so he wasn't going to make that mistake again. That's why he didn't call any of the other girls families. He is sadistic, not stupid.
SK's aren't capable of empathizing with the victims, so I don't think there was any special bond of any sorts. I do agree, MB sounded as though she could get pretty feisty. I would hope that they all did fight back or make him angry. If he did become enraged at her (or any of the girls) he most likely took it out on her at that moment, rather than hold it in and release it on the sister through a later phone call.
AB said he was calm when he called. I don't believe he called her for any reason other than to taunt the family to maintain prolonged control. He may have had the intention of calling the other families too, but later decided not to risk it.
One last thing, AB visited MB several times at her home in the Bronx. I believe he was stalking her in both the Bronx and in Buffalo, so I'm sure it was just a matter of putting 2 & 2 together that "Amanda = Little Sister."
(My stalking theory is under "Geographical Profiling.")
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