“If we had known what would happen, we’d never have written that graffiti,” says Mouawiya Syasneh in The Boy Who Started The Syrian War, a recent Al Jazeera documentary that tells his story.

Mouawiya was 14 and in the seventh grade when he sprayed anti-government slogans on a school wall in Deraa in February 2011, never thinking his mischievous act of youthful defiance would spark a war that’s left over half a million dead.

“We saw what was happening in Egypt and Tunisia,” he tells Al Jazeera, referring to the Arab Spring. “So we got together at school, took some paint and sprayed the walls. We wrote on the school wall, ‘Your turn next, Doctor [Assad].’ A few days later the police saw what we’d written and rounded up the boys in the neighbourhood.”

Mouawiya’s three accomplices were arrested by the police, together with a dozen other suspects. Mouawiya was arrested at home at 4am and driven away in handcuffs. He was detained for 45 days and tortured. “The electric shock treatment was the worst,” he tells Al Jazeera. “They took me to the bathroom and it was really wet and they would turn on the shower. They ran the current through the water and onto my back. I felt the shock wherever the water went.”

When their fathers tried to find out what had become of the boys, they were told, “Forget those children; go home and make some more. If you can’t manage, send us your women and we’ll make more for you.”

Fearing for the boys’ safety after a month in police custody, thousands began taking to the streets demanding their return. When the peaceful protests were met with further violence, they spread. Soon this was no longer a protest over the arrest of some young boys; it had become an uprising.

“When I got out, I was surprised by all the protests,” says Mouawiya. “There were mass demonstrations.  It was chaos. We went and joined in when we saw what was happening. We were happy. I suppose we felt all this support was for us.  All these people were out on the street, for us.  But we didn’t know that a crackdown was coming.”

Mouawiya had dreamt of going to university. “I wanted to study business and economics,” he says. But his dreams were shattered by the war, especially after his father was killed in an airstrike in Deraa in 2013, plunging his family into poverty. “When he was killed, I felt lost in the world,” says Mouawiya.

He saw only one option open. “I felt I must take up arms and fight,” says Mouawiya. “It was a big moment in my life. I wanted to fight for the Free Syrian Army (FSA).

Just four weeks after joining the FSA, Mouawiya was shot and wounded in the leg. His best friend, Amaar, joined the FSA on the same day but was less fortunate, and is buried at the edge of town.

“I didn’t expect this to happen,” says Mouawiya. “No one expected this against civilians.  We didn’t expect all the destruction. Later on, we started to feel we’d messed up and made a huge mistake.”