The assassination was never going to take place. On Tuesday, FBI Director Robert Mueller described Iranian American Mansour Arbabsiar's alleged plot to assassinate the Saudi Ambassador to the United States as straight out of a "Hollywood script."
In a sense he was right—because the plot was controlled from the beginning by the FBI. According to the criminal complaint, when Arbabsiar traveled to Mexico in May 2011, to allegedly find an assassin from the ranks of Mexican drug cartels, he ended up talking to a paid DEA* informant who dodged drug charges in exchange for cooperating with authorities.
In keeping with previous sting cases, the FBI was careful to record statements from Arbabsiar dismissing the possibility of numerous civilian casualties, something that makes an entrapment defense all but impossible to mount.
The US thinks Iran is responsible. The criminal complaint states that Arbabsiar believed his cousin, Ali Gholam Shakuri, was a member of the al-Quds Force, an elite faction of Iran's Revolutionary Guards.
Under interrogation, Arbabsiar allegedly identified two men who were "known to the United States to be senior members of the Quds Force," one of whom allegedly met with Arbabsiar and Shakuri in Iran to discuss the operation. Despite the al-Quds Force's reputation for lethal effectiveness however,
Arbabsiar and his cousin don't come off as any more competent than the average target of an FBI sting. They discuss the plot in ham-handed "code" in telephone conversations, and Shakuri allegedly wires $100,000 to an American bank controlled by the FBI.