Olli Heinonen, the Finnish nuclear engineer who resigned Thursday after five years as deputy director for safeguards of the International Atomic Energy Agency (IAEA), was the driving force in turning that agency into a mechanism to support U.N. Security Council sanctions against Iran.

Heinonen was instrumental in making a collection of intelligence documents showing a purported Iranian nuclear weapons research programme the central focus of the IAEA's work on Iran. The result was to shift opinion among Western publics to the view that Iran had been pursuing a covert nuclear weapons programme.

But his embrace of the intelligence documents provoked a fierce political struggle within the Secretariat of the IAEA, because other officials believed the documents were fraudulent.

Heinonen took over the Safeguards Department in July 2005 - the same month that the George W. Bush administration first briefed top IAEA officials on the intelligence collection.

The documents portrayed a purported nuclear weapons research programme, originally called the "Green Salt" project, that included efforts to redesign the nosecone of the Shahab-3 missile, high explosives apparently for the purpose of triggering a nuclear weapon and designs for a uranium conversion facility. Later the IAEA referred to the purported Iranian activities simply as the "alleged studies".

The Bush administration was pushing the IAEA to use the documents to accuse Iran of having had a covert nuclear weapons programme. The administration was determined to ensure that the IAEA Governing Board would support referring Iran to the U.N. Security Council for action on sanctions, as part of a larger strategy to force Iran to abandon its uranium enrichment programme.

Long-time IAEA Director-General Mohammed ElBaradei and other officials involved in investigating and reporting on Iran's nuclear programme were immediately sceptical about the authenticity of the documents. According to two Israeli authors, Yossi Melman and Meir Javadanfar, several IAEA officials told them in interviews in 2005 and 2006 that senior officials of the agency believed the documents had been "fabricated by a Western intelligence organisation".

Heinonen, on the other hand, supported the strategy of exploiting the collection of intelligence documents to put Iran on the defensive. His approach was not to claim that the documents' authenticity had been proven but to shift the burden of proof to Iran, demanding that it provide concrete evidence that it had not carried out the activities portrayed in the documents.

From the beginning, Iran's permanent representative to the IAEA, Ali Asghar Soltanieh, denounced the documents as fabrications. In Governing Board meetings and interviews, Soltanieh pointed to several indicators, including the absence of official stamps showing receipt of the document by a government office and the absence of any security markings.

The tensions between Heinonen and the senior officials over the intelligence documents intensified in early 2008, when Iran provided detailed documentation to the agency disproving a key premise of the intelligence documents.

Kimia Maadan, a private Iranian company, was shown in the intelligence documents as having designed a uranium conversion facility as part of the alleged military nuclear weapons research programme. Iran proved to the satisfaction of those investigating the issue, however, that Kimia Maadan had been created by Iran's civilian atomic energy agency solely to carry out a uranium ore processing project and had gone out of business before it fulfilled the contract.

Senior IAEA officials then demanded that Heinonen distance the organisation from the documents by inserting a disclaimer in future agency reports on Iran that it could not vouch for the authenticity of the documents.

Instead Heinonen gave a "technical briefing" for IAEA member countries in February 2008 featuring a diagram on which the ore processing project and the uranium processing project were both carried out by the firm and shared the same military numbering system.

The IAEA report published just three days earlier established, however, that the ore processing project number -- 5/15 -- had been assigned to it not by the military but by the Atomic Energy Organisation of Iran. And the date on which it was assigned was August 1999 - many months before the purported nuclear weapons programme was shown to have been organised.

Heinonen carefully avoided endorsing the documents as authentic. He even acknowledged that Iran had spotted technical errors in the one-page design for a small-scale facility for uranium conversion, and that there were indeed "technical inconsistencies" in the diagram.

He also admitted Iran had provided open source publications showing spherical firing systems similar to the one depicted in the intelligence documents on alleged tests of high explosives.

Heinonen suggested in his presentation that the agency did not yet have sufficient information to come to any firm conclusions about those documents. In the May 2008 IAEA report, however, there was no mention of any such caveats about the documents.

Instead, the report used language that was clearly intended to indicate that the agency had confidence in the intelligence documents: "The documentation presented to Iran appears to have been derived from multiple sources over different periods of time, is detailed in content and appears to be generally consistent."

That language, on which Heinoen evidently insisted, did not represent a consensus among senior IAEA officials. One senior official suggested to IPS in September 2009 that the idea that documents came from different sources was not completely honest.

"There are intelligence-sharing networks," said the official. It was possible that one intelligence organisation could have shared the documents with others, he explained.

"That gives us multiple sources consistent over time," said the official.

The same official said of the collection of intelligence documents, "It's not difficult to cook up."

Nevertheless, Heinonen's position had clearly prevailed. And in the final year of ElBaradei's leadership of the agency, the Safeguards Department became an instrument for member states - especially France, Britain, Germany and Israel - to put pressure on ElBaradei to publish summaries of intelligence reports portraying Iran as actively pursuing a nuclear weapons programme.

The active pressure of the United States and its allies on behalf of the hard line toward Iran was the main source of Heinonen's power on the issue. Those states have been feeding intelligence on alleged covert Iranian nuclear activities to the Safeguards Division for years, and Heinonen knew that ElBaradei could not afford to confront the U.S.-led coalition openly over the issue.

The Bush administration had threatened to replace ElBaradei in 2004 and had reluctantly accepted his reelection as director-general in 2005. ElBaradei was not strong enough to threaten to fire the main antagonist over the issue of alleged studies.

ElBaradei’s successor Yukio Amano is even less capable of adopting an independent position on the issues surrounding the documents. The political dynamics of the IAEA ensure that Heinonen's successor is certain to continue the same line on the Iran nuclear issue and intelligence documents as Heinonen's.