I think the fact that she'd already been waiting for 15 minutes, that it was quite late, that she'd said she'd only be there for an hour, and that she was really looking forward to seeing her boyfriend, might have led her to get into any car that offered her a ride, even if it seemed a bit suspicious... Given the circumstances, it seems highly unlikely that she left alone... And she wasn't wearing shoes? Why would she leave without shoes? There's no way she would have started a new life without them... Something bad happened to that girl that night...
Whatever the case,
rest in peace.