Iran's journalists in chains from Committee to Protect Journalists on Vimeo.

Journalism can be a tough gig for Iranians, who face secrecy and the risk of retribution, and it seems to be getting tougher. A video by the Committee to Protect Journalists shows a rising trend in reporters being imprisoned for such charges as "insulting the supreme leader" or "spreading propaganda against the state;" in other words, for doing journalism. Some have faced solitary confinement, forced confessions, even death.

That trend started getting worse, the press freedom group says, shortly after Mahmoud Ahmadinejad was elected president in late 2005. And it got much, much worse after the disputed 2009 presidential election, in which mass protests called for a recount but were ultimately put down by security forces.

Here, from a recent Committee to Protest Journalists report on Iranian press freedom abuses, is the cumulative – and, presumably, desired – effect of those arrests. (My emphasis added.)

As devastating as the imprisonments are to the individual journalists and their families, the Iranian government’s tactics have had an intimidating effect on the press, choking off the flow of information. This census and CPJ’s past surveys are simply snapshots in time—they do not include the large numbers of journalists convicted of crimes or facing charges who are temporarily free on bail or furlough. Iran has pursued a revolving-door policy in imprisoning journalists, freeing some detainees on short-term furloughs even as they make new arrests. The pattern of rotating critical journalists in and out of prison has sown fear and self-censorship across the entire press corps, according to CPJ research. At least 68 Iranian journalists fled into exile between 2007 and 2012 due to harassment and the threat of imprisonment, according to CPJ research. Only Somali journalists have gone into exile in higher numbers during that period.

The Washington Post's Jason Rezaian reported in January about Iranian journalists who had been arrested for allegedly working with foreign media such as the BBC.