On 8 January I sent a video of the protests in Iran to a friend in England. Then the internet went dark. Reza Pahlavi – the son of the late shah, now living in the US – had called for people to come out into the streets at 8 p.m., in response to the catastrophic economic situation and the strikes that had begun in the bazaars a week earlier.

I live on the top floor of a block of flats in western Tehran. I turned off the lights and watched the city below. It was slowly changing shape. Shops were closing. People were running through the streets. My phone rang. It was a friend. ‘We’re going to Qeytarieh Square,’ he said. ‘Come with us.’

We headed north in a car. Along the way, shopkeepers were pulling down their shutters. When we arrived, I couldn’t believe the size of the crowd. People in wealthy neighbourhoods never usually protested. But economic pressure had erased class distinctions. Discontent had become universal.

The chants were loud: ‘Long live the Shah’; ‘Death to Khamenei.’ Wanting to know what was happening further ahead, I moved forward and got separated from my friends. Sandbags and dirt were piled in the middle of the street. Road signs had been torn down to block the entry of security forces. Someone poured petrol onto a pile of tyres and set it on fire. The flames rose high, lighting up the street.

Across from us stood riot police in full gear, twenty or thirty of them, along with armed plainclothes agents. I looked at the protesters around me. Most of them were very young, perhaps twenty years old: girls and boys dressed in dark clothes, their faces covered by masks. ‘Don’t go into side alleys,’ people warned. ‘You’ll get trapped.’

The police fired tear gas. The chants continued. ‘They’re shooting!’ someone shouted. We all ran. A young woman asked me to look at the back of her neck. She had been hit by pellets.

The sound of gunfire intensified. I could see flashes in the darkness and didn’t understand what they were. (Later, when the internet came back on and videos surfaced on social media, I realised the authorities had been firing directly into the crowd.)

Seeing the young woman who had already been shot was enough for me. I headed back towards my friend’s car. To avoid being identified none of us had our phones. There was no way to be in touch with one another. But my friends were waiting for me.

We drove back to western Tehran, toward Sadeghieh Square. The streets were filled with fire. We tried different routes to avoid the crowds. Near the square, there were so many people the streets were impassable. I got out of the car and ran towards home.

Suddenly I found myself in the middle of violent clash. Plainclothes agents were attacking people with batons. The sound of gunfire didn’t stop. Protesters were trying to flee, carrying the wounded.

A boy was lying at the side of the road with a plainclothes agent sitting on him. The agent’s arm was moving up and down, yet he held no baton. I moved a little closer. He was stabbing the boy with a knife. I ran.

It took me half an hour to get home. I was worried about my family, but the phone and internet weren’t working. I didn’t dare turn on a light. From the window, I watched the gunfire and tear gas below. The city finally fell silent around three in the morning.

People were supposed to return to the streets again at eight the following evening. At dusk, around five o’clock, the shops began closing. The security forces were out in far greater numbers. From my window, I could see riot motorcycles and armoured vehicles with three men in the back, one of them standing behind a mounted machine gun. A few hours later the sound of gunfire was so intense that it felt like a war zone.

On 10 January I went to buy bread. Bakeries are usually places of quiet conversation, but that day anger was visible on people’s faces. The queue was long, and in the course of an hour I witnessed two serious altercations.

The internet was still down. ATMs weren’t working. It was possible to make phone calls but not to send texts. The only incoming messages were from the government:

Following public demand for firm action against those disrupting security, citizens are requested to report any suspicious individuals or elements threatening security by calling 114, 113 or 110.

Dear parents, due to the enemy’s plan to increase open violence and deliberately cause civilian deaths, please remain alert to these plots and avoid being present in streets or gatherings where violence is taking place. Also, inform your children about the consequences of co-operating with terrorist mercenaries, which is considered an act of betrayal against the country – IRGC Intelligence Organisation

Report any suspicious activity.

The people who had been called ‘rioters’ the day before were now labelled ‘terrorists’. Additional warnings were issued: any contact with the outside world or sharing of images would be severely punished.

A few days later, my brother called me. ‘There’s no good news,’ he said. ‘I heard that our cousin has been arrested.’

I live near one of the Islamic Revolutionary Courts, which handle alleged threats to national security. Since the start of the protests, two or three hundred people have been gathering outside the courthouse daily.

A man said that his son, a soldier, had been arrested on his way to the barracks. Judges were issuing verdicts based on interrogation reports: did he take videos? Did he throw stones? Punishment could be a fine, property confiscation, jail time or even a death sentence.

We still have no news of my cousin. We only know that he has been detained.

On 13 January, Iran International television announced that over the course of just two days, twelve thousand people had been killed. They broadcast images from the Kahrizak Medical Forensic Centre, showing bodies piled on top of one another. BBC Persian spoke more cautiously of thousands of deaths. Iranian state television at first announced a figure of two thousand. Two weeks later, some unofficial estimates place the number killed at more than 36,500.

In the absence of reliable information, rumours became a parallel reality. Numbers were whispered in queues, repeated without certainty but with conviction. What everyone knew for sure was that death had entered daily life.

I stopped driving for Snapp!. It didn’t seem safe and I was scared to go back to driving nights. But one day I called a Snapp! car and took it to a café to meet a friend. I asked the driver to turn the radio on. ‘I’ve boycotted radio and television,’ he said. ‘They assume we’re idiots and lie to us.’

His main job was driving an ambulance, he told me, but that didn’t pay enough to survive. He had been on duty on 10 January. ‘Just me alone,’ he said, ‘I transported four hundred bodies to Kahrizak.’

He spoke calmly, almost mechanically. ‘The scenes I saw will stay with me for the rest of my life. Over those two days – 8 and 9 January – they killed so many people that bodies were stored in mosques. We were only operating around the Tehran Bazaar. When they ran out of vehicles, they used hospital ambulances. I can say this comfortably: they killed 100,000 people.’

He told me about a woman who came to collect her husband’s body. According to those accompanying her, the man had leaned out of a window to see what was happening and was shot in the head. His body fell into the street. His wife and daughter watched as security forces put his body in a black bag and carried it away. The wife ran downstairs. Her husband’s blood was still warm on the pavement. The daughter had stopped speaking.

When the woman came to retrieve her husband’s body, the driver told me, the authorities demanded payment for the bullet. She showed them a cloth soaked in her husband’s blood and said she would bury that – and they could keep the body.

Tehran is in mourning. In this collapsed economy, perhaps the only people who continue to earn an income are sellers of dates, halva and candles – because at mourning ceremonies it is customary to distribute dates and halva, and to burn candles, constantly, in homes and on pavements.

I arranged to meet a friend at a café and took a shared taxi to get there. The woman beside me was muttering blessings (salavat) under her breath. She said she was praying for conditions to improve.

‘Our problem as people is that we throw everything into God’s court,’ the driver said. ‘God gave us the tools for life. The rest must be managed with reason. Nothing gets fixed with prayers and blessings.’

At the café I asked my friend how business was. He owns a women’s clothing store in the bazaar. ‘I closed the shop,’ he said. ‘There are no sales at all. Like you I’ve started driving Snapp! at six in the morning and work until ten at night. Maybe I get two hours of rest in between. I make about 20 million rials a day, 600 million a month. My rent is 280 million rials. Food prices go up every day. How am I supposed to live?’

He said people think America is coming with warships to overthrow the clerics. ‘They’re not coming for that. They’re coming to stop oil exports. Even if we sell oil, they don’t pay cash. They give us Chinese goods. What use are cars to us? We need money, not barter.’

‘If America attacks Iran,’ I said, ‘won’t people be killed?’

‘They don’t kill people. Our own government does. No enemy in our history has done to us what these clerics have done.’

What is said in private cannot be spoken in public, on pain of death. A new billboard towers over a busy highway in Tehran. On one side is a black-and-white photo of Abolhassan Banisadr, the first president after the revolution who was impeached in 1981. On the other is a colour photo of Masih Alinejad, a journalist who left Iran in 2009 and is now a US citizen and prominent critic of the regime. Between them are the words: ‘A traitor is still a traitor.’