Mr Sazegara, who ran the www.alliran.net website, was arrested in Tehran on 15 June 2003 after publishing an article calling for 'a profound change of the constitution'.
In a previous letter to the Ayatollah Khamenei, leader of the Islamic Republic, Mr Sazegara says the leader is responsible for the system which is ignoring the needs of the people and that 'he is not afraid of the leader'.
Amnesty reports that 48-year-old Mr Sazegara, who was due to be released on 25 August, is being held without charge despite his family posting bail of 600 million Tomans (around US $722,000).
On 1 September, internet news site Peyk-e Iran reported that Said Mortazavi, chief prosecutor for Tehran province, had prevented Mr Sazegara’s release. Later that day, a statement released by the Iranian judiciary stated that Mohsen had not been released because of a file of 'unspecified allegations against him' dating from 2002.
Amnesty is concerned that Mr Sazegara may have been tortured or ill-treated while in detention and the latest report from Iran, sent to Amnesty on 2 September, indicated that he is in a poor state of health.
Mr Sazegara has been on hunger strike since his arrest and also has a heart condition. Amnesty believes that his medication may have been withheld, and that the authorities appear to be refusing to allow his family and his lawyer to see him.
Mr Sazegara was also imprisoned in February 2003 for another article critical of the Ayatollah published on alliran.net.
Amnesty is urging supporters to join the final round of appeals for Mr Sazegara. UK media director Lesley Warner told dotJournalism how the public can support the campaign.
"The key thing is to sign up for our urgent action emails," she said.
The emails explain how to write protest letters to the relevant authorities. In 2002, Amnesty sent 468 urgent action emails, each of which triggered between 3,500 and 5,000 responses.
"These emails give brief details of the case and who to write to. We also suggest legally appropriate phrases and the correct salutations that are most likely to illicit a response."
Amnesty is demanding that Mr Sazegara be released immediately and without condition, and is seeking to clarify the charges under which he is being held.
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