Despite Iranian denials, the story about a plot to assassinate the Saudi envoy to Washington fits the profile of Iran's notorious Revolutionary Guards.
A peculiar murder plot - which fits with IRGC rhetoric
In the days following the US Department of Justice's press conference on the foiled terror plot "directed by elements of the Iranian government to murder the Saudi Ambassador to the United States", officials of the Islamic Republic have energetically dismissed the allegations.
That, however, belies years of threats from Iran's state and security apparatus to carry out just such a plot.
Parliamentary Speaker Ali Larijani, in an effort coordinated with the state-run Iranian media, has tried to divert blame by identifying one of the suspects in the case, Gholam Shakuri, as a member of the dissident group the People's Mujahideen of Iran (MEK). That too fits a pattern of Iranian officials casting about for US conspiracy theories.
In one of the more bizarre allegations, Ala Al Din Boroujerdi, the parliament's national security and foreign policy chairman, said the US allegations were "diverting public attention from the revolt against Wall Street".
Brig Gen Hossein Salami, a deputy of the Islamic Revolutionary Guards Corps (IRGC), which the United States accuses of masterminding the plot, dismissed the story as a design to "instigate discord between Shia and Sunni".
Supreme Leader Ali Khamenei's statements late last week might have been a precursor to a theory that has since been advanced: "By making senseless and baseless allegations against a few Iranians, [the US] tried to find a pretext to condemn the Islamic Republic of Iran as a sponsor of terrorism, but this conspiracy too was defeated."
This is a usual line for Iranian officials, but they were not the only ones dismissing the US allegations. Robert Baer, a former CIA case analyst, said "the attack did not appear to have been planned by Iran", pointing out "sloppiness" that he found uncharacteristic of the IRGC's Quds force, the foreign operations arm of the Guard.
Prof Juan Cole of the University of Michigan, a long-time observer of Tehran, did not rule out the possibility of a government plot, but found it more plausible that a "rogue Iranian drug cartel with an IRGC cover" was responsible.
Such scepticism is understandable. Iran does not show restraint in terrorising dissidents inside the country or, for that matter, assassinating members of the Iranian opposition abroad, but plotting the murder of the Saudi ambassador to the US does not fit Ayatollah Khamenei's cautious character.
But who else could have authorised the plot? It fits the pattern of statements made by IRGC commanders since Saudi Arabia sent troops to Bahrain in March.
In April, Sobh e Sadeq, the mouthpiece newspaper of the IRGC, condemned Saudi Arabia's deployment to Bahrain: "They have chosen the dangerous path of suppression and they must certainly pay a very high price for it." The same month, Maj Gen Yahya Rahim Safavi, a former Revolutionary Guards commander and the military adviser to Ayatollah Khamenei, warned of "foreign intervention" in Saudi internal affairs.
The mission of the Quds force in overseas operations has been cast increasingly in terms of intervention in Arab countries. Also in May, Maj Gen Qassem Suleimani, the Quds force commander, said: "Today, Iran's victory or defeat is no longer decided in Mehran or Khorramshahr [western Iranian cities that were on the front line in the 1980s war with Iraq]. Our boundaries have expanded and we must witness victory in Egypt, Iraq, Lebanon and Syria."
This thinking is based on the doctrine that supporting terrorist groups abroad could provide Iran with a powerful deterrent in the face of hostile powers. IRGC threats against the United States have become more direct as well, which fits with allegations that the assassination plot would be carried out on US soil. Last month, Mohammad Reza Naqdi, the commander of the Basij militia, said "not all interventions should be western; we are also prepared to intervene in the internal affairs of these countries when needed".
But at this point, theories about power plays within the Iranian leadership structure cannot be discounted either. The diplomatic crisis between Iran and Saudi Arabia, and more importantly Iran and the US, plays into the hands of hardliners in the Guard.
The Iranian public is bound to hold President Mahmoud Ahmadinejad responsible for the hardships of life in a country burdened by sanctions, and his faction has little chance of future political success unless he delivers tangible improvements in the living conditions of the voters.
However, any improvement in Iran-US relations would be a catastrophe from the viewpoint of the IRGC, which has systematically used the American "Great Satan" to rally the disgruntled Iranian public around the flag and to legitimise its interventions in all spheres of life in Iran.
This was, after all, the lesson the Guard learnt in the 1980s war, when crisis mended divisions within the Guard and among political factions and paved the way for further power for the IRGC's commanders.
The official denials and conspiracy theories will still come like scattershot. But unless an MEK connection to a plot proves credible, Tehran has some fundamental questions to answer.
Whether or not Ayatollah Khamenei or the IRGC is found to be responsible for the plot, the US has no other choice but to hold Iran in its entirety responsible.
If the US failed to respond decisively, it would send wrong signals to friends and foes alike: allies would find themselves deserted, while foes would test Washington's red lines more aggressively in the future.
Ali Alfoneh is a resident fellow at the American Enterprise Institute