Police have made a major development in the case of the headless woman found partially dismembered in a suitcase in south Tel Aviv on Saturday, the Jerusalem Post has learned.The development, which is still covered under a gag order, should help police find the people responsible for the murder.The woman was found on a staircase to the pedestrian bridge to HaHagana train station in south Tel Aviv on Saturday afternoon, by bomb sappers called by a passerby.The investigation is being handled by the Tel Aviv branch of the YAMAR investigative unit.Police have still not found the head.