Indeed, the same letter indicates that Zamani had been repeatedly threatened by intelligence agents who described several possible scenarios for his death. Furthermore, suspicion is unlikely to fall on his fellow prisoners, not only because of the virtual impossibility of murdering him in his own cell but also because he was very well-liked within the prison. Since his death, fellow inmates have been demanding information from prison officials, but they have refused to elaborate on the circumstances of his death. No formal investigation appears to be forthcoming.

IranWire notes that Zamani’s is only one of a number of suspicious deaths in Rajai Shahr Prison in recent years. In many cases, the prison authorities respond to sudden deaths by simply listing the cause as “stroke” and moving the body out of the facility very quickly, forestalling any real chance of a detailed inquiry. Given the record of prisoner abuse throughout Iran, there is little question that at least a portion of these deaths are the result of foul play.

The NCRI indicates that Zamani’s corpse was reportedly found with bruising around the head and a mouthful of blood. Even discounting this evidence, it is unlikely that the 51 year-old’s death was from natural causes, since all reports indicate that he was in exceptional health.

What’s more, IranWire notes that the imprisoned labor activist had been continuing his work on labor rights from inside the prison and had been assembling some writing the evening before his death. He has also been documenting day-to-day goings on inside the prison, presumably including the poor conditions and mistreatment faced by political prisoners as well as conventional inmates.

Interestingly, the International Campaign for Human Rights in Iran published an article just two days before the discovery of Zamani’s death, in which it described the urgent need for labor rights activism in Iran, where labor unions and similar organizations are illegal. Due in large part to this lack of organized representation, the number of workplace-related deaths have been climbing in recent years. In the period between March and July alone, 650 such deaths have been recorded, putting the country on pace to exceed the 1,000 death figure recorded in 2013 and to possibly double the 700 deaths recorded in 2004.

The International Campaign notes that even these numbers are conservative estimates, and that this is even more true of the more than 10,000 injuries recorded between March and July. Some injuries go unreported out of fear of firing or retaliation, and the Iranian government often avoids accurately reporting the circumstances of death in the workplace, as well as in prisons. This demonstrated pattern of behavior leads many statistical reports about deaths both in and outside of Iranian prisons to be accompanied by notes contending that they may fall short of the real figures.

This interest in secrecy ostensibly provides prison officials and the regime itself with a motive for either murdering Zamani or unintentionally causing his death through excessive punitive measures. Many other prisoners and arrestees have been subject to retaliation from the regime in the past after they exposed the conditions and experiences of other Iranian prisoners, as Zamani was apparently in the process of doing.

For instance, artist and women’s rights activist Atena Farghadani was ordered to not speak publicly about her treatment after she was arrested for the crime of posting a political cartoon to Facebook criticizing a number of Iranian officials. She refused and went on to post a YouTube video explaining what political prisoners might be faced with upon arrest. This defiance may in turn have contributed to the severity of the 12 year and nine month sentence she received for charges of spreading propaganda and insulting the supreme leader.

Many others have similarly ordered to remain silent and steer clear of the media after being arrested for activities on social media, and many of them have abided by those orders.

These cases and Zamani’s death all represent the role of censorship and suppression of information under the Iranian regime, as well. In the context of the story of Zamani’s death, IranWire notes that many inmates in Rajai Shahr Prison have been complaining about the presence of satellite jamming equipment on the roof of the facility, which is aimed at effectively barring political prisoners from contacting or regularly receiving information from the outside world.

The strength of the jamming signal has been increased over time, and some inmates now report headaches and worry that the equipment will have consequences to their health – something that is especially a concern in a prison system where conventional and political prisoners are frequently denied medical attention, even when preliminary examinations find that specialty care is necessary to safeguard the life of the inmate.

The denial of medical care adds to the roster of known or possible victims of mistreatment in the Iranian prison system. And even these represent only a portion of the abuses endemic to that system. A good deal of press has been given to another key aspect of that problem: the skyrocketing rate of executions ordered by the Iranian judiciary.

The NCRI reported that Zeid Ra’ad Al Hussein, the UN’s high commissioner for human rights, had once again raised the issue of Iran’s executions in the opening of a session of the UN Human Rights Council on Monday. Hussein referred to the execution of more than 600 people in the first half of the year. Most reports, including that of the UN special rapporteur for human rights in Iran, find that the total to date easily exceeds 700 and gives Iran an overall average rate of about three executions per day.

There are a number of ongoing calls for action on this dramatic over-use of the death penalty. But Zamani’s suspicious death has led to calls for investigations into other types of deaths within the Iranian criminal justice system. NCRI President Maryam Rajavi, for instance, called for an international mission to investigate all suspicious deaths that have recently occurred or may occur in the future in Iranian prisons.