IIRC- It has been reported on several occasions that MAS was/is bipolar and had been on medication as recently as earlier this year when she went for treatment at the same location as the woman whose house she and TS stayed at when they dyed their hair. If she is on medication for a bipolar disorder, then her memory loss might not be as unbelievable as we are suspecting. A quick Google search pointed out that Lithium treatment does have memory loss side effects. Mix in any stimulants and/or depressants, and the effects are magnified. Also, I read a couple of reports that said when a patient is in a manic or psychotic state, as when meds are not taken properly, memory loss can occur and can be a total loss if extreme.
I'm starting to wonder again, if drugs and alcohol use (whether at a private party with Jaren, MAS, and TS, as was implied by other dancers, or at a much larger gathering) resulted in Jaren possibly overdosing and MAS and TS panicking because now they were in possession of a dead body that they could not take back to NOLA. Knowing that the recent questionable death of Hillary Moulder could somehow be tied to them, or that their drug connections could put them at risk of an even greater threat from their suppliers, the two decided they would cover for each other to any extent- whether they remembered exactly what happened or not. If Jaren did OD, would a stab wound to the chest have made the rest of the horrible crime any easier to commit, by making sure she was definitely not still alive and possibly lessening blood loss during the dismembering??
I just realized I'm typing in the middle of a quote and have messed up this long post. Sorry!