I believe that there was only one target and here’s why: It’s not super uncommon for girls of this age to sleep in the sand bed in a non sexual manner, especially when coming back from the bars; I know plenty of pairs of girls that lived together in college that would do this. When you factor in that KG was graduating early and getting ready to leave it wouldn’t surprise me if they were in the same room. Especially when you look at the fact that they both called the ex boyfriend. Perp walks in the sliding glass doors in the back, up the stairs to whichever girls room was the target, finds both MM and KG, stabs them both, as perp is walking back downstairs, EC hears the disturbance and confronts them, he’s murdered, <modsnip: rumor>, and XK is stabbed as well as she witnessed EC’s murder. This explains the girls downstairs being spared as well. Just my opinion