One part of this does make sense. Right after the murders, the reports said that the victims all seemed to be caught off guard. There was no sign of forced entry, and the D.A. never appeared to reach for his gun. If this lady actually is the killer, then it makes sense that they would have opened the door and let her in without a fight, because they knew her.
Aside from that, it's crazy that people can be this disturbed. We are seeing a lot of that lately.