Majid Tavakoli, Ahmad Ghasaban, and Ehsan Mansuri were among eight student editors and activists arrested on accusations that they defamed Islam in student publications. The other five students have been freed.
Charges against them reportedly include inciting public opinion and insulting Iran's leaders. But rights activists and student groups say the charges are "fabricated," and that the students were jailed in retaliation for a protest against Iranian President Mahmud Ahmadinejad, who visited the university in December.
A Long List Of Abuses
The families of the three detained students have addressed an open letter to the head of the country's judiciary, Ayatollah Mahmud Hashemi-Shahrudi, in which they describe ill treatment and torture that they say is aimed at coercing false confessions.
The detainees' families say the students have been deprived of food and sleep, beaten unconscious, and interrogated for hours.
The detainees' families say the students -- all in their early 20s -- have been subjected to physical and psychological pressure ranging from verbal abuse to beatings with cables. The long list of abuses that they claim the students have faced in prison includes sleep and food deprivation -- for up to 48 hours -- and denial of medical care.
They say the students have been interrogated for hours on end by a team of seven interrogators who have beaten and punched them into unconsciousness.
They add that the students were forced into "insupportably tiresome" positions for long periods -- including being made to stand on one leg for 18 hours -- or have been held sometimes in solitary confinement in cramped prison cells and at other times among dangerous criminals.
The letter to the judiciary chief -- published on several Iranian news websites -- also says that authorities have used threats of murder against the students and their families.
Pressure To 'Confess'
Arman Sedaghati is a Polytechnic University student and a member of Iran's largest pro-reform student group, the Office To Foster Unity (Daftare Tahkim Vahdat). Sedaghati told Radio Farda that he's been told that the detained students have been under tremendous mental pressure.
"Ghasaban's mother suffers from heart problems, and in his cell they were playing the sound of a heartbeat," Sedaghati said. "Also, once, they told him he was free but then -- when he went to the gate of Evin prison -- they took him back and put him back in solitary confinement."
Sedaghati says families learned about the plights of their loved ones after they were transferred to a public ward. "[The frequency of] their telephone calls increased after they were transferred to the public cell, and [the students] could inform their parents about the kind of torture they were subjected to, as well as its intensity," he said.
The families think the pressure is aimed at forcing the detainees to confess to the charges against them.
They say such confessions would have no value, and asked the head of the judiciary, "How much torture can a 22-year-old youngster bear?"
Rights groups and student activists are warning that about 15 students who have been in jail since July 9 are facing similar pressure to confess.
Last week, footage of two Iranian-American scholars detained in May appeared on an Iranian television program titled "In The Name Of Democracy." The program linked Haleh Esfandiari, the director of the Middle East program at the Woodrow Wilson International Center for Scholars, and Open Society Institute urban-planning consultant Kian Tajbakhsh to what has been described by Iranian authorities as a U.S. plot to destabilize Iran's Islamic establishment.
Read the Persian-language open letter
from the students' families to Iran's judiciary chief
Human rights groups, their families, and colleagues say the two were clearly forced to appear in the televised segments. They point to Iran's past record of broadcasting bogus confessions by critics and intellectuals after detentions on security charges.
Iranian officials claim the "comfortable surroundings" in which Esfandiari and Tajbakhsh appeared prove that they were not subjected to abuse. Tajbakhsh appeared in a room with a television set and bookshelves, while Esfandiari was sitting on a couch in a room with potted plants.
Two other Iranian-Americans -- Radio Farda journalist Parnaz Azima and Ali Shakeri, a founding board member at a California university's Center for Citizen Peacebuilding -- have also been detained or had their freedom curtailed on security-related charges.
Iranian government spokesman Gholamhossein Elham said on July 22 that Tehran does not employ violence against its opponents. He said that "giving the accused a hard time and pressuring them is not our policy."
Yet the letter by the families of detained students and testimony from former political prisoners suggest that critics who end up in Iranian prisons face difficult conditions, including isolation and physical abuse.
(Radio Farda broadcaster Farin Assemi contributed to this report)