There's good circumstantial evidence to support it, but no conclusive by any means. The Tanzanian connection looks promising, as do statements by Pak officials, but it is hard to miss the increasing vehemence of denials by the Pak government that this is not the case. If we have him, the powers that be don't want it known.
Here is a good, but long article that sums up the latest in Pakistan:
http://www.counterpunch.org/huggler08042004.html