Riot police had driven off anti-government demonstrators and the sting of tear gas in the air was fading yesterday when the heavy-set man in a camouflage uniform grabbed me, shouting in Farsi, and pushed me into a throng of riot police.
They shouted while I waved my hand and said "Canadian" to no effect. Before I knew what was happening, I was whisked away on a motorcycle to the Interior Ministry headquarters, and taken to a large basement room.
Inside a concrete room to my left, I could see more than 50 others being made to stand in uncomfortable positions - on their toes with their hands pressed behind their heads. Some were covered in blood, and police with batons patrolled the rows, tapping some detainees on the shoulders with their sticks.
There was no screaming, just the sound of boots pacing on the concrete floor.
For a few terrifying hours yesterday, I was mistaken for an anti-government protester, giving me a glimpse into how the hundreds arrested over the weekend are being treated by authorities in a system where dissidents are known to "disappear" and not be seen again for months.
It all started when a few hundred supporters of Mir-Hossein Mousavi rallied yesterday to protest against the defeat of their candidate.
Men and women shouted slogans, waved flags and called for an end to the government of Mahmoud Ahmadinejad. Just like the day before, when election results were first released showing a bigger-than-expected victory for Mr. Ahmadinejad, police dressed in jet-black riot gear charged the crowd with batons, fired tear gas and struck whomever straggled behind.
Plainclothes officers hand-picked whomever they could, throwing them in vans and on black motorcycles to be driven off to unknown places.
I was walking by a checkpoint and an officer grabbed me and forced me onto a motorcycle. As soon as we stopped, I was grabbed from the bike by another officer and slapped across the head. Seven officers ran up to join in the slapping, and one punched me in the head. A large officer, about 6 foot 4 and dressed in camouflage, grabbed me by the neck, pinching my jugular but not my windpipe. His leather gloves cut through my skin and I was pinned against a van, my arm bent high behind my back.
I was then thrown onto a second motorcycle with one police officer in front of me and another behind, slapping me more and cursing during the quick ride around the corner.
When we stopped, an officer grabbed me, pinned my arm behind my back and led me into the bowels of the Interior Ministry headquarters - where so many Iranian dissidents "disappear."
We went down several flights of dark concrete stairs to a large basement room, where I was grabbed by the shirt and pinned against the wall, as more questions were shouted at me in Farsi - and as I caught glimpses of the others being treated far worse. I was separated from the protesters, and officers gathered around me, attracted by the spectacle of a foreigner.
Some pushed me, and I was worried I would be held and beaten for days. But two of the officers fended the others off. They took my camera to see whether I had photographed the riots, but I had already erased the images. I was questioned in broken English for about 20 minutes - sometimes held against the wall, sometimes allowed to stand while officers smiled and chatted.
A man then came downstairs and led me back up the dark staircase to the front of the building where a friendly, English-speaking officer photocopied my passport and press credentials.
"There has been a terrible misunderstanding," I was told. "There is a bad situation in Tehran, and sometimes the officers get confused," he said with a smile, while a plainclothes officer offered me water and tea.
In an almost surreal gesture, they introduced me to the riot police officer standing nearby, who shook my hand and said, "You are my friend," and, "Canada is good."
The officer told me I was free to go, and I was allowed to walk out of the Interior Ministry building with nothing more than bleeding welts on my neck and a swollen arm.
My journalist credentials and Canadian passport got me out of the Interior Ministry building, but dozens of others remained in that basement.