When reports emerged earlier this month that prominent Iranian Internet entrepreneur Arash Zad had been arrested in August at Tehran's Imam Khomeini airport, it was unknown who apprehended him, or why.
But suspicion has since fallen on the Islamic Revolutionary Guards Corps' (IRGC) intelligence arm, whose increased activities could indicate that Supreme Leader Ayatollah Ali Khamenei has rejuvenated the much-feared unit so he can gain greater control over the country.
The unit's resurgence appears to coincide with Hassan Rohani's ascension to the presidency in the summer of 2013, after which the relative moderate set about trying to live up to his campaign promises to give Iranians more freedoms and move away from his predecessor's heavy handed approach to dissent.
That, observers say, potentially puts Rohani at odds with Khamenei, who as supreme leader has ultimate say in the Islamic republic. The IRGC's intelligence unit, which falls under the supreme leader's direct authority, could serve as a useful tool if Khamenei cannot fully trust the Intelligence Ministry to do as he wishes.
There is precedent for the supreme leader and the hard-line faction of the Iranian establishment to use the IRGC unit or others as a parallel intelligence apparatus -- Iran witnessed a surge in the operations of alternative intelligence bodies under former reformist President Mohammad Khatami, whose attempts at reform were blocked by hard-liners.
"The intensity of their [the IRGC intelligence unit's] activities and actions against domestic critics and activists depends on to what extent the Intelligence Ministry, which is controlled by the government, satisfies Khamenei," explains Virginia-based political analyst Ali Afshari.
The head of the Iran desk of the French media watchdog Reporters Without Borders (RSF), Reza Moini, says his organization has recorded the arrest of more than 100 bloggers and Internet activists in Iran since August 2013, when Rohani took office.
Washington Post reporter Jason Rezaian, who went on trial in August on espionage charges, and popular spiritual leader Mohammad Ali Taheri, who's been sentenced to death, are reportedly among the IRGC unit's recent targets. The unit, which controls a section in Tehran's Evin prison, was reportedly involved in the state crackdown that followed the 2009 mass antigovernment protests.
"More than 89 percent of these [individuals] have been arrested by the intelligence unit of the IRGC in Tehran and other cities," Moini says. "They've faced unfair trials and sentenced to heavy prison sentences."
The unit's activities are seen as part of the IRGC's efforts to control the Internet, described by hard-line officials as a threat and a platform for Iranian "enemies" to influence the country.
In most cases, according to Moini, the IRGC has leveled "fabricated" charges against the individuals and sent them to jail. "The judiciary is not independent," he says. "The IRGC makes the decisions."
Khamenei has recently called on the IRGC's intelligence unit to monitor and identify threats, in what some observers see as a sign that the unit could further escalate its repressive measures in the months ahead.
The call followed warnings by Khamenei and other officials in recent weeks against the potential for "infiltration" by Iran's enemies emboldened by the prospect of closer relations and greater access to Iran after the recent accord on the country's contentious nuclear activities.
The supreme leader last week warned that "economic and security infiltration is not as important as intellectual, cultural, and political infiltration."
Khamenei called for vigilance and said that the IRGC, which is tasked with defending Iran against internal and external threats, has an important role to play.
"The intelligence branch of the IRGC must monitor all issues at all times and identify threats," Khamenei told IRGC commanders on September 16, according to a text of his speech posted on Khamenei.ir.
Afshari, who was arrested and tortured by the IRGC's intelligence unit under President Khatami, is not surprised to see its revival as a parallel intelligence body.
"Under Rohani the Intelligence Ministry has been trying to distance itself from methods used under [former hard-line President Mahmud] Ahmadinejad," Afshari notes.
Fears Of A Clampdown
Providing some insight into the kinds of methods used by the unit, he recalls being beaten up, subjected to sleep deprivation, and forced to confess to crimes dictated by his interrogators.
"They wanted me to give them all the information I had about political forces and [confirm] their [prewritten] scenarios," Afshari recalls.
Aliasghar Ramezanpour, a London-based journalist who served as deputy culture minister under Khatami, says that the supreme leader appears now to be laying the groundwork to give the IRGC's intelligence unit more power.
"Khamenei is very clearly stressing the need for increased activities by IRGC's intelligence unit. I think [it means] that the unit will have a freer hand," said Ramezanpour.
In practice, he says, it could mean more arrests and allow the unit to create a more restrictive environment ahead of the 2016 elections for parliament and the Assembly of Experts, which is tasked with electing and removing Iran's supreme leader.
Ramezanpour suggests the IRGC could work with the powerful Guardians Council to keep candidates whose views are deemed out of line with the clerical establishment from running.
After years of being repressed and sidelined, Iranian reformists are hoping to make a political comeback in next year's elections.
Hard-line officials, including members of the Guardians Council, have warned that "seditionists" -- a term used to describe members of the Green opposition movement that protested Ahmadinejad's disputed reelection in 2009 -- will be prevented from winning seats.