In January, the Iranian authorities detained eight members of the Persian Wildlife Heritage Foundation, with one, Iranian-Canadian university professor Kavous Seyed Emami, dying under suspicious circumstances in prison in February. Shortly after his death, another environmentalist was picked up.

The letter, signed by 1,124 people and posted on Monday to a a Telegram channel dedicated to Emami, asked Sadeq Larijani to transparently resolve the case’s “ambiguities” in a way that respects the detainees’ dignity, but does not explicitly call for their release in the way that many others have.

The signatories, who include environmentalists, artists, current and former government officials, and other civil society activists, wrote that the detainees have not engaged in unlawful activity, which implies that they should be released, and are renowned for their work in protecting Iran’s wildlife.

Mohammad Hossein Aghasi, an Iranian lawyer who has sought to represent the detainees, said in October that the judiciary changed its charges against five of the accused from espionage to “sowing corruption on earth”, which carries the death penalty.

On October 24, during a news conference to announce the revised charges, Tehran’s chief prosecutor, Abbas Jafari Dolatabadi, accused the detainees of “seeking proximity to military sites under the cover of environmental projects and obtaining military information from those sites”.

This came after an Iranian Parliament committee, including Iran’s environmental department and intelligence ministry, examined the case in May and found no evidence of spying, suggesting that the Iranian Regime is just throwing any charges at detainees in the hope that they stick.

The Iranian state-run news agency IRNA referenced the committee’s findings in a report on Monday about the civil society activists’ letter to Larijani and quoted Iranian Vice President Isa Kalantari, who heads the environmental department, as saying that the powerful Iranian judiciary has blocked him and other officials from taking further action in the case.

Last month, Hadi Ghaemi, the head of New York-based Center for Human Rights in Iran, said that nothing could justify the continued detainment of the environmentalists, let alone their execution.

He said: “One detainee has already lost his life during this travesty of justice. Iran should immediately release the remaining detainees to prevent further loss of innocent life.”