It wasn't until 1995, when Saddam Hussein's son-in-law defected from Iraq to Jordan, that U.N. investigators first began to grasp just how much Iraq was still concealing -- and not just about biological warfare.
Hussein Kamel told officials that Iraq had obtained enriched uranium from France and Russia.
Days after Hussein Kamel's defection came even bigger revelations, when box loads of secret Iraqi documents mysteriously turned up on a Baghdad chicken farm.
It was a treasure trove of weapons secrets, touching almost every aspect of Saddam Hussein's illegal war machine.
To Ekeus -- demonized by Iraq for years as a brutal skeptic -- the documents brought vindication.
"Iraq stated that they had declared everything," Ekeus recalls. "Iraq stated that no documents existed in Iraq because they had been destroyed. That was exploded totally, because Iraq itself admitted in writing even that it had been lying, cheating systematically from when we started in 1991 up until this very date in August of 1995."
There was, however, a huge piece of the puzzle still missing --- production details of Iraq's biological weapons program.
"They have the ammunition, I imagine, the bombs and maybe some missiles hidden," Ekeus contends. "And there are something like 80 biological facilities ranging from research to storage -- and they are fully equipped. And certainly most important, the expertise that resided in the biological weapons program is intact."