I don't think there was a rape involved. I think she was killed during the bombing, they didn't have time to bury her or the means to take her with them so they left her. I think she was dead for long enough for the blood to coagulate, the other side came upon her, lifted her clothing to expose her belly, stabbed her and used the blood to make the insignia. Go back and and look at the video again, look at the wound mark close to the insignia, it protrudes inwards, doesn't appear to be fresh blood but where the skin goes down in the wound it appears dried and dark.