I'm trying to come up with a scenario where DA knew something she didn't/couldn't say, but wasn't involved in the disappearance, planned or otherwise. Regardless of what she knew, what is the reason she didn't say. To me, that reason can only be she didn't want to implicate herself, Tommy (and/or his associates?) or her own family (potentially including Rachel herself) in something OR fear of retribution on herself, Tommy (and/or his associates) or her own family or again, Rachel herself. Or BOTH implication and retribution, which would mute her indefinitely. I stay with the fact there's a good chance DA didn't know the disappearance was even imminent or certainly permanent, but maybe she declined going w/Rachel because she knew or assumed something hinky was going down at one of the stops pre-SS. I'd like to believe her own sister wouldn't let Rachel walk into her own execution, so I'm guessing DA envisioned something far less dramatic she didn't want to be a witness to or be bothered with that she nonetheless thought would go smoothly.
Could Rachel have unknowingly made a sketchy 'errand' stop? It could be DA said "oh, thanks but I can't go to SS, hey... while you're out can you stop at XYZ for me?" Or even "can you pick up something from the XYZ, no one should be there so just check the top drawer." If not the A/N, where else might they have stopped we don't know about? Rachel may have simply been a messenger re drugs, shady-business deal on behalf of TT or DA, etc. She also may not have even know details of what she was messengering. If she showed up somewhere with less money than was owed, or worse an excuse or "My (sister, husband, etc.) said to tell you they don't have it yet, can I have more time?" I can see someone flipping out with threats and/or injury. Even worse if she was rooting around for something and was 'caught' by someone who didn't know who she was (though I think she'd be known). A pissed off liaison makes the most sense if Rachel went into a building/home by herself and Renee and Julie were in the car (a big car where their heads might not be seen in an sunny glare...esp little J in the back). Any number of scenarios could have happened, which led to 2 more completely unintended witnesses. Rachel flees to her car and the perp is seen, or Rachel doesn't leave and the girls are discovered waiting in the car, or liaison follows them thinking it's just Rachel but sees the other two heads and fears she's telling them what happened. Whatever it is, we went from 1 problem for this person to 3.
Third scenario is perp lets an oblivious Rachel go, but is simmering. At some point goes to mall and abducts Rachel who he'd only seen solo before and is just now realizing there are 3. That would explain accounts the trio was seen at SS that day, but not necessarily the ballsy move of a triple abduction, unless perp got reinforcements on the way. But maybe that seemed like less of a trail than having a potential mess wherever this started. Of course, he'd have no way of knowing who else they saw in the mall and how much Rachel was talking.
I'd love to know what calls were made to DA and TT from the time Rachel was seen at A/N to that night, as well as outgoing from the businesses. And exactly how many people knew Rachel was going to the mall, or might have mentioned to someone else. Without cell phones, there was definitely enough lag time to make some impulsive, catastrophic decisions w/o thinking it through or being called off or calmed down.
