Iran arrested more than a dozen journalists, bloggers, opposition supporters and rights activists in recent weeks, intensifying a crackdown on freedom of expression ahead of parliamentary elections in March.
Three website developers were also sentenced to death earlier this month "for spreading corruption on earth". Each had languished in jail for at least four years, so the timing of their sentences, just weeks before the polls, was not seen as coincidental.
That those held seem particularly unthreatening is aimed at fostering a climate of fear and stifling the free flow of information before the election, analysts said.
It will be the first nationwide vote since June 2009 when President Mahmoud Ahmadinejad's re-election was challenged by hundreds of thousands of Iranians taking to the streets.
The wave of arrests and draconian sentences also highlights the regime's paranoia as it grapples with internal divisions and unprecedented western pressure over its nuclear programme. Human-rights groups have said Iran is already the world's leading jailer of journalists and its most prolific executioner.
Parastou Dokouhaki, an award-winning blogger and women's- rights activist in her 30s, has been held in solitary confinement in Tehran's Evin prison since January 15 when security agents stormed her home. Because of harsh restrictions on the media, she had not been involved in journalism in recent years and was not politically active.
Ms Dokouhaki was also crippled by depression over her father's death a few months earlier and receiving treatment for a serious illness. On December 31, in her last posting on her blog, Zan Nevesht (Woman Writer), she wrote that time was not easing her grief for her father. Exposure to the "painful process" of his "long sickness and death" has "left me vulnerable", she wrote. "I am dying bit by bit … I am sick … I am deeply depressed … I don't have any motivation for creating even small goals."
Ms Dokouhaki has been charged with "acting against national security" and "propaganda against the regime".
Two days after her arrest, Marzieh Rasouli, an award-winning music and literary critic for reformist newspapers, was hauled off to Evin in similar circumstances on the same charges. She was never politically active. Within hours, a photojournalist, Sahamoddin Bourghani, the son of a prominent reformist former parliamentarian, was also detained.
Among others arrested this month were Simin Nematollahi, who wrote for a website covering news about Sufis; Mohammad Soleimaninya, the head of a social networking site; and Said Madani, a civil rights activist.
Human-rights groups have also highlighted the plight of three website developers on death row, the most prominent of whom is Saeed Malekpour, an Iranian-born resident of Canada. He was arrested in 2008 while visiting his dying father. Held for a year in solitary confinement without access to lawyers, he was found guilty of promoting adult websites and "agitation against the regime".
Mr Malekpour, 36, has denied the charges and said he was subjected to "physical and psychological torture" in detention. After an international campaign, his death sentence was overturned last summer but reconfirmed by Iran's Supreme Court this month when he lost his final appeal.
Amnesty International said that by confirming Malekpour's sentence "after an unfair trial, the Iranian authorities are sending a message to Iranians not to freely express their views, or even to help others to do so, including on the internet".
Iran this month announced plans to launch a "halal", or pure, national intranet, which the country's online community fears is intended to replace the global internet, cutting off cyber access to the outside world.
Before previous elections, the authorities eased up on the media to encourage high voter participation, which they claim is popular endorsement of the regime's legitimacy. Not so this time.
The regime is still jittery after the mass unrest ignited by Mr Ahmadinejad's "stolen" election in 2009 shook the clerical establishment to its core.
"This is the first election in three decades that the regime is actually increasing suppression before the vote," said Sadeq Sabaa, head of the BBC's Persian service.
Iran has forbidden the channel to have staff in Tehran, but tries to intimidate its reporters abroad by harassing family members in Iran, Mr Sabaa added in an interview from London.
Mir-Hossein Mousavi and Mehdi Karrubi, the reformist leaders who ran against Mr Ahmadinejad in 2009, have been under house arrest since last February. Most reformists are boycotting the March 2 polls. Mr Karrubi last month accused the regime of intending to hold a "rubber stamp" election.
The vote will instead be a contest between rival ruling hardline factions that were united against the opposition Green Movement three years ago but who are now at each other's throats.
Supporters of the supreme leader, Ayatollah Ali Khamenei, accuse the president of trying to sideline Iran's clergy and Revolutionary Guards who enjoy immense power, privilege and wealth.
It is unlikely that either hardline faction can stage a large show of people power on the streets like the reformist Green Movement did in 2009. But any confrontation between them could be more destabilising.
Unlike the reformists they "have access to different levers of power - economic, political and military", Hadi Ghaemi, the New York based co-ordinator of the International Campaign for Human Rights in Iran, said.
As in 2009, the regime is trying to blame its internecine problems on foreign enemies. Iran's intelligence minister, Heidar Moslehi, announced the arrest of several unnamed "spies" this month.
Iran is second only to China in the number it executes. By last November, Iran had executed at least 600 people in 2011, 81 per cent of them for drug-related offences, Amnesty International said last month.
The New York-based Committee to Protect Journalists, meanwhile, described Iran as "the world's worst jailer" of journalists, with 42 behind bars in December.
A well-informed Iran analyst, who requested anonymity, said others were detained this month whose cases have not come to light because the authorities threatened their families not to make them public. He expected more arrests as the election nears.