That's why I'm curious as to the definition of rape/penetration with an object. I wonder if that's his MO (as others have speculated), and we, quite fortunately, have a living witness to tell us. Hannah and Morgan can't, and their bodies/clothes might not have told us either if that's the case.
JMO, but I think he just never made it that far before being frightened off by the passerby; I think he toys with his victims, even to the point of degradation and torture. Again, JMO.