ppaul posted a link to a series titled "The Terrorist Within" on 6/24/04. This was the (surprisingly!)terrific series on Ahmed Ressam, the millenium bomber, published by the Seattle Times.
The key info on the Immigration officer is in chapter 12...but if you have time to read it, it is a real eye opener on how the Clinton Administration had NOTHING to do with breaking this case.
Mark Steyn has written about this as well. As far as I know, the customs agent's instincts saved the day, with no help from Rowley, the FBI, or any other government agency.