From an MSNBC article written in 1998:
http://www.nbcnews.com/id/3340101/t/bin-laden-comes-home-roost/#.XrubumhKjD4
BIN LADENS BEGINNINGS
As anyone who has bothered to read this far certainly knows by now, bin Laden is the heir to Saudi construction fortune who, at least since the early 1990s, has used that money to finance countless attacks on U.S. interests and those of its Arab allies around the world.
As his unclassified CIA biography states, bin Laden left Saudi Arabia to fight the Soviet army in Afghanistan after Moscows invasion in 1979. By 1984, he was running a front organization known as Maktab al-Khidamar - the MAK - which funneled money, arms and fighters from the outside world into the Afghan war.
What the CIA bio conveniently fails to specify (in its unclassified form, at least) is that the MAK was nurtured by Pakistans state security services, the Inter-Services Intelligence agency, or ISI, the CIAs primary conduit for conducting the covert war against Moscows occupation.
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a rich Saudi boy gone to war and welcomed home by the Saudi monarchy he so hated as something of a hero.
In fact, while he returned to his familys construction business, bin Laden had split from the relatively conventional MAK in 1988 and established a new group, al-Qaida, that included many of the more extreme MAK members he had met in Afghanistan.
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Given that context, a decision was made to provide Americas potential enemies with the arms, money - and most importantly - the knowledge of how to run a war of attrition violent and well-organized enough to humble a superpower.
That decision is coming home to roost.