I don't question that member(s) of the A family may've had ties to OC. What I do question, is why should OC be so kind as to help "clean up"/dispose of three girls' bodies?
I seriously can't imagine any scenario in which it would make sense with DA.
Cause okay, possible, why not. Many things are possible. Let's say that she was with whatever reason not just a random girl working at one of these clubs, trying to support herself but significantly connected to the OC members or even bosses.
Then why she ended up living with Rachel and TT? Why didn't she took advantage of these connections in order to get some room/flat/home alone?
Maybe cause abduction was planned and she planted herself there to track her sister, waiting for the perfect moment when she will be with other girls, valuable in human trafficking business?
Her assumed connections should significantly decrease the probability of her being so, so much into TT that she would just straight away jump into helping him cover up for triple murder of minors. What kind of man, raised in the 50's and 60's (or even earlier) and involved in OC would be so chilled about the girl he's fond of or sort of loyal to, that he'd continue supporting her and covering up for her while she'd suddenly request help with hiding bodies of three minors that her ex fiance, now BIL just murdered?
So maybe back to grand scheme with planned abduction with her being planted there to help.
She did that, all tracks covered, full success. Then what?
What could it be there for her to keep her mouth shut? Monetary gain - possibly. All thing being some form of repaying her debts - possibly, maybe, huge stretch but maybe. Maybe cold blooded revenge on Rachel for stealing such a gem-boy from her. Maybe some other unforeseen reasons. Maybe.
But then what could be there for these OC members/bosses in keeping some (still) freaking unstable teenager with drug issues alive and basically free of their infuence? Maybe she wouldn't know much of their secrets, maybe she would be (in the scenario) unable to prove anything, cause any realistic damage or issue. Maybe. But in such scenario those people would be the only ones there fully aware that she's capable of selling her sister and two other kids for slavery, sending them for torture and death, or being involved in their murders, or having no issue with casually helping with covering up for her BIL who just randomly felt like murdering three minors.
IF DA were that kind of girl, with such... personality, of basically next level psycho, then - at least IMO, only completely dumb and insane person would let her go and leave the ties with OC.
Cause she would either have extemely valuable potential in OC business - so just all the reasons to give her whatever she wants to keep her around and engaged in more illegal activities, more schemes...
... or she would be potentially dangerous like hell for them, no gain in keeping her alive, just risk, big risk, serious risk and unnecessary risk.
Long story short, I don't see OC involvement through DA as possible. Thinking about it causes me to picture some poorly written villain from the crime-action novel.
IMO the only realistically probable ways in which OC could be involved in this would be:
1. Maybe even through DA, but withher being used as an excuse to show up around and fish foe some info, watch Rachel without DA's knowledge that there is some abduction/murder plan behind this,
2. Unrelated to the family members at all.
3. Through a person with long lasting ties with OC, with long established loyalty, someone who already managed to prove it left and right that they're not causing trouble for OC, keeping their job done and mouth shut.
I doubt DA's secrecy alone, would be sufficient. We're talking Organized Crime, here. There would have to be some sort of "payment" or "arrangement"-- assurance of silence-- from everyone involved. IMO
It would be interesting to know if either DA's or TT's finances after this showed any indication of blackmail, etc. Did TT have access to anything around that time, or have any connections (maybe through his parents), that would give him "leverage"?
How much were those savings bonds worth that were said to be missing from the Olds (that were allegedly later found)?
There is no indication that either of them had multiple-murder-related-blackmail kind of money.