For people around the globe, the images of club-wielding men on motorcycles beating demonstrators on the streets of Tehran was just another case of brutality in a far-off land.
But as he watched the violence of recent weeks unfold on television and YouTube, Amir Farshad Ebrahimi, an exiled Iranian, recognized some of the attackers.
They were once good friends.
His life, encapsulating the betrayals and disappointments that followed Iran's tumultuous revolution 30 years ago, as well as the hopes and fears of Iranians now living abroad, had come full circle.
Once a lonely young man in exile, a rejuvenated Ebrahimi is now using his experience as an insider within Iran's hard-line militias to "out" members of the group.
On his well-regarded Persian-language blog, he has listed the names and phone numbers of about a dozen militia members whom he has spotted in photos and video of the demonstrations over his homeland's disputed presidential election.
One of them rang him up in a tizzy. "This is unethical," his onetime friend told him.
Ebrahimi was flabbergasted. "You're killing people," he said. "Isn't that more unethical?"
Why was the 11-year-old spending so much time at the mosque, Ebrahimi's family wondered. What was he doing after school, hanging out with the sons of those detested "Hezbollahis," Islamic radicals who had dominated the country after the 1979 revolution?
His father, an air force pilot, was no true believer. After returning from lengthy stints at the front of the Iran-Iraq war, he would immediately shed his fatigues, shave off his beard and curse those who headed the war effort as incompetent fanatics.
But young Ebrahimi was enchanted by the country's new spirit, lured by the confident young men who signed up to fight.
"The boys kept saying, 'Let's go to the mosque,' " he recalled. "There were always displays of guns and grenades there. I liked it."
In 1987, the 12-year-old and a friend lied about their ages, evaded their parents and signed up to fight on the front lines during the war's penultimate year.
"They gave us a little money and a train ticket and told us to report for duty," said Ebrahimi, who provided photographs showing him as a fresh-faced youngster in uniform.
One day his father came to the base. He approached his son, slapped him hard on the face, then walked away without saying a word.
After 10 months, Ebrahimi returned home, and though he hadn't seen much action, he was hailed as a hero, a big shot among his peers.
The gawky teenager began writing patriotic pieces for a youth magazine called Surah, catching the attention of hard-line groups.
He signed up for the Islamic Revolutionary Guard Corps and was accepted into a university, hanging out with like-minded students and veterans.
They met regularly, usually at mosques. They studied literature called "Program of the Guardianship," which included lessons about Islam and politics, and depicted their political rivals, including reformists, as enemies of God, in effect giving themselves permission to kill their foes without committing a sin.
"We were brainwashed," Ebrahimi said. "We thought that these people had taken up swords and were going against Islam."
Among those he befriended was Mojtaba Khamenei, the son of Iran's supreme leader, Ayatollah Ali Khamenei. They went on trips together, visiting the resort towns of the Caspian Sea coast on weekends or for holidays.
Eventually they would evolve into the group called Ansar-e Hezbollah, now notorious as the informal shock troops of Iran's hard-line establishment loyal to the supreme leader.
The way Ebrahimi had envisioned it, Ansar-e Hezbollah was a political and cultural organization. So why were they talking about beating people? He didn't like that.
It was early July 1999, just before the student unrest and crackdown that symbolized the height and the downfall of Iran's reformist wave under then-President Mohammad Khatami.
Ebrahimi's Ansar-e Hezbollah colleagues wanted to crush the students. He urged restraint, hoping the movement would burn itself out.
A week later, exactly 10 years ago today, 18th day of the month of Tir on the Persian calendar, Ansar-e Hezbollah activists stormed the dormitories, killing one student, probably more.
Ebrahimi had seen enough and, in a now famous act, waded into a crowd of students to take the podium.
"You're right," he told the stunned audience. "They're savage. I've resigned."
The students roared with approval.
The next day, he was arrested outside his home, shoved into the trunk of a car and taken to an unknown building and locked in solitary confinement.
During grueling interrogations, he suffered a broken chin and hand, was hung by his feet and beaten.
After eight months, he was dropped off in downtown Tehran, but his freedom was short-lived.
Ebrahimi was again arrested, tried and sentenced to prison, shuttling from Tehran's infamous Evin Prison, where demonstrators today are being taken, to other facilities in and around the capital for three years.