DUBAI, United Arab Emirates -- In his last blog entry, activist Sattar Beheshti wrote that Iranian authorities had given him an ultimatum: Either stop posting his "big mouth" attacks against the ruling system or tell his mother that she will soon be in mourning.
"We will tear down your cruel cage," Beheshti typed on Oct. 29 before signing off.
A day later he was arrested. Within a week, his family had collected his body. They began calls for an investigation that have been echoed by Washington, Europe and rights groups.
The 35-year-old Beheshti apparently fell under the custody of Iran's cyber police, created last year with a wide mandate to crush Web dissent. The powers displayed in the case -- including questioning Beheshti outside the regular justice system -- suggests a level of autonomy and authority that could bring far more aggressive measures against Web activists.
"There's no question that the Internet is seen by Iran's rulers as a threat and something that needs to be tightly controlled," said Theodore Karasik, a regional security expert at the Dubai-based Institute for Near East and Gulf Military Analysis.
Iran's Supreme Leader Ayatollah Ali Khamenei often refers to the need for stronger measures in the "soft war" playing out in cyberspace with the West and opposition groups.
The Islamic Republic already tries to block dissident websites and has jailed several well-known bloggers, including Hossein Derakhshan, who helped ignite the Iranian blog boom in 2001 by posting simple instructions to create sites in Farsi. In March 2009, a 29-year-old blogger, Omidreza Mirsayafi, died while being held at Tehran's Evin Prison.
Last month, the UN's Office of the High Commissioner for Human Rights warned of "a further severe clampdown on critical voices" in Iran. Even a former Iranian intelligence minister, Ali Younesi, called Beheshti's death in custody a "disaster" for Iran's leaders.
Last week, Iran's state prosecutor Gholam Hossein Mohseni Ejehi said Beheshti was detained for alleged cybercrimes and handed over to cyber police for interrogation.
The coroner's report said the body had "signs of wounds" in five places, the semiofficial Mehr news agency quoted Ejehi as saying. But on Thursday, the Tehran prosecutor's office raised the possibility Beheshti could have died from "excessive psychological stress," suggesting that authorities are looking into causes of death other than abuse for the final report.