Here is my new take. There were numerous rumors that Eliza was dealing. Here me out now. You have the security guard and the couple that both said they were very uncomfortable about the guys at the booth. The couple said they were creepy and gave off a bad vibe. The security guard made the same observation about the guy letting people cut in line. However, Eliza was not phased by them, she was very comfortable with them and allowed them to go back and forth from the front to back. What if Eliza knew them, what if they were there to do a deal. What if they were also there to collect on money Eliza owed for past product she got on credit. The guys are maybe there to collect, deal, and are going back and forth from booth to bathroom in order to do some crystal. The store closes and Eliza asks for more product. The guys, under the influence, act tough, telling her she owes some money first. Maybe they disrespect her. One of the other girls (Amy), not liking this, gets in the face of the guys. The guy hits or pushes her. Now you have the other girls jumping in. This is a melee. The guys produce weapons to control the melee. Now the guys are in another more crazed state, adrenalin, drugs, financial compensation. Maybe one of the girls threatens police involvement, maybe Amy or one of the other girls was hurt. The guys realize they are in for a penny in for a pound. Events deteriorate into violence, rapes, etc. The girls know who the guys are, so they cannot be left alive. They are executed and burned. The scoop is left in Amy because perhaps there anger is at her the most for her defiance. The money required for Eliza's debt is taken from the register. There could have been no intent for murder at the start, but the effect of the drugs and the escalation of events by the girls' aggressive response, kicked off a crazed and hysterical event. If these guys were strangers, there just would have been no reason for killing four girls. I think they were known to the girls. When you examine so many mass killings, drugs inevitably comes up, so often. And I am not disrespecting Eliza, I had friends in high school and college that moved small amounts, they were not bad people, usually they were party people. She did have an expensive car that also required expensive parts...