While the administration of Barack Obama vows to hold the Iranian government "accountable" for the alleged plot to assassinate the Saudi ambassador in Washington, the legal document [.pdf] describing evidence in the case provides multiple indications that it was mainly the result of an FBI "sting" operation.

Although the legal document, called an amended criminal complaint, implicates Iranian-American Manssor Arbabsiar and his cousin Ali Gholam Shakuri, an officer in the Iranian Quds Force, in a plan to assassinate Saudi Arabian Ambassador Adel al-Jubeir, it also suggests that the idea "originated with and was strongly pushed by a undercover DEA informant, at the direction of the FBI."

On May 24, when Arbabsiar first met with the DEA informant he thought was part of a Mexican drug cartel, it was not to hire a hit squad to kill the ambassador. Rather, there is reason to believe that the main purpose was to arrange a deal to sell large amounts of opium from Afghanistan.

In the complaint, the closest to a semblance of evidence that Arbabsiar sought help during that first meeting to assassinate the Saudi ambassador is the allegation, attributed to the DEA informant, that Arbabsiar said he was "interested in, among other things, attacking an embassy of Saudi Arabia."

Among the "other things" was almost certainly a deal on heroin controlled by officers in the Islamic Revolutionary Guard Corps (IRGC). Three Bloomberg reporters, citing a "federal law enforcement official," wrote that Arbabsiar told the DEA informant he represented Iranians who "controlled drug smuggling and could provide tons of opium."

Because of opium entering Iran from Afghanistan, Iranian authorities hold 85 percent of the world’s opium seizures, according to Iran’s Fars News Agency. Iranian security personnel, including those in the IRGC and its Quds Force, then have the opportunity to sell the opium to traffickers in the Middle East, Europe and now Mexico.

Mexican drug cartels have begun connecting with Middle Eastern drug traffickers, in many cases stationing operatives in Middle East locations to facilitate heroin production and sales, according to a report last January in Borderland Beat, an online news service run by University of Arizona journalism students.

But the FBI account of the contacts between Arbabsiar and the DEA informant does not reference any discussions of drugs.

The criminal complaint refers to an unspecified number of meetings between Arbabsiar and the DEA informant in late June and the first two weeks of July.

What transpired in those meetings remains the central mystery surrounding the case.

The official account of the investigation cites the testimony of the informant (referred to in the document as "CS-1") in stating, "Over the course of a series of meetings, ARBABSIAR explained to CS-1 that his associates in Iran had discussed a number of violent missions for CS-1 and CIS-1′s purported criminal associates to perform."

The account claims that the mission discussed included murdering the ambassador. But no specific statement proposing or agreeing to the act is attributed to Arbabsiar. "Prior to the July 14 meeting, CS- 1 had reported that he and Arbabsiar had discussed the possibility of attacks on a number of other targets," the account states.

The targets are described as involving "foreign government facilities associated with Saudi Arabia and with another country…located either in or outside the United States," without mentioning any discussion of the Saudi ambassador.

Both that language and the absence of any statement attributed to Arbabsiar imply that the Iranian- American said nothing about assassinating the Saudi ambassador except in response to suggestions by the informant, who was already part of an FBI undercover operation.

The DEA informant, as the FBI account acknowledges in a footnote, had previously been charged with a narcotics offence by a state in the U.S. and had been cooperating in narcotics investigations – apparently posing as a drug cartel operative – in return for dropping the charges. The document is notably silent on whether the conversation was recorded.

A former FBI official familiar with procedures in such cases, who spoke to IPS anonymously, said the FBI would normally have recorded all such conversations touching on the possibility of terrorism.

The absence of quotes from any of those meetings suggests that they do not support the case being made by the FBI and the Obama administration.

The account is quite explicit, on the other hand, that the Jul. 14 and Jul. 17 meetings were recorded at FBI direction. Statements quoted from those transcripts show the DEA informant trying to induce Arbabsiar to indicate agreement to assassinating the Saudi ambassador.

The informant is quoted as saying he would need "at least four guys" and would "take the one point five for the Saudi Arabia." He declared that he "go ahead and work on the Saudi Arabia, get all the information we can."

At one point the informant says, "You just want the, the main guy." And at the end of the meeting, he declares, "[W]e’re gonna start doing the guy."

The fact that not a single quote from Arbabsiar shows that he agreed to assassinating the ambassador, much less proposed it, suggests that he was either non-committal or linking the issue to something else, such as the prospect of a major drug deal with the cartel.

Arbabsiar’s quotes from a Sep. 2 phone conversation referring to the cartel as "having the number for the safe" and "once you open the door that’s it" could refer to a drug transaction that had been discussed, while the FBI account suggest those quotes refer to the assassination and "other projects" with the Iranian group.

At the Jul. 17 meeting, the DEA informant presented a plan to blow up a restaurant to kill the ambassador, with the possible deaths of 100-150 people, eliciting a lack of concern on the part of Arbabsiar about such deaths.

During a visit to Iran in August, Arbabsiar wired two equal payments totalling $100,000 to a bank account in New York. But he was still under the impression that he was about to cash in on a deal with the cartel.

The Washington Post reported Thursday that Arbabsiar had told an Iranian-American friend from Corpus Christie, Texas, "I’m going to make good money."

There is also circumstantial evidence that Arbabsiar may have even been brought into the sting operation to help further implicate his cousin Gholam Shakuri in the terrorist plot.

Arbabsiar met with his cousin Shakuri in late September and told him that the cartel was demanding that he, Arbabsiar, go to Mexico personally to guarantee payment. That demand from the DEA was an obvious device by the FBI to get Shakuri and his associates in Tehran to demonstrate their commitment to the assassination.

The FBI account indicates that Shakuri told Arbabsiar that he was responsible for himself if he went to Mexico. That statement would have been a warning sign for Arbabsiar, if he still believed he was dealing with one of the most murderous drug cartels in Mexico, that he would be risking his own life for a group that was no longer taking responsibility for him.

Yet Arbabsiar flew to Mexico as if unconcerned about that risk.

After his arrest on Sep. 29 Arbabsiar waived the right to a lawyer and proceeded to provide a complete confession. A few days later, he placed a phone call to Shakuri which was recorded "at the direction of federal enforcement agents," according to the FBI.

Read more by Gareth Porter

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• Former Insiders Criticize Iran Policy as US Hegemony – February 25th, 2013
• Bulgarian Revelations Explode Hezbollah Bombing ‘Hypothesis’ – February 17th, 2013
• Iranian Bomb Graph Appears Adapted from One on Internet – December 13th, 2012
• News Media Misled by IAEA Data on Sensitive Iranian Stockpile – November 20th, 2012