That's an excellent idea: do search about Black September: The stories propagated by PPP are about complete lies. Don't rely upon one political statement or the other (there is one statement by PLO related person as well, when campaign against Zia was carried out in Pakistan) but go through the timeline (lingering 2+ years) and actual events, numbers and the role of zia if you find any , timing and the mission of PA or Pakistan ) - Not to support Zia but, as far as I have looked through the Jordan-PLO conflict in that era, this allegation is against the facts on the ground and generally PPP propaganda. The rest you may search for yourself to find the truth.