Nairobi, Kenya (CNN) -- A white bus drives through Nairobi at midnight. It looks like the type tourists hire to drive out on safari but this one is stuffed with a gang dressed in black hoodies.
They target Kenya's political elite with a single message-- they are graffiti artists whose work likens their nation's political leaders to vultures.
"We tried many other animals like the hyena but the closest animal that describes a Kenyan politician is the vulture. They prey on the weak," says Boniface Mwangi, a Kenyan photographer and the group's leader.
Mwangi marshals his artists at a blank white wall next to a bank.
A graffiti artist named Uhuru focuses a tiny projector onto the murky wall as Bankslave and Smokey spray the first black outlines. They put up traffic cones to make it all look a bit more official.
But only a handful of glue-sniffing homeless wander over to look.
Mwangi is an award winning photo-journalist who has shelved his journalism career, putting his successful commercial photography business at risk.
He says the vulture art is making waves. "We have been able to change the language of the country, now politicians are being referred to as vultures by the mainstream media. And that's what we wanted that people can define the leaders for what they are."
A single moment he captured with his camera changed his life.
"There is one memorable photo," he says. "I saw a girl who had been shot and she looked like my sister. That broke my heart."
It was early 2008 and post-election unrest engulfed Kenya. Mwangi witnessed the unraveling of his country through a lens: In one image a couple stands over a dead man left on the side of the road in the rain; in another, a moment just before the impact of a machete, and then a severed hand still grasping a makeshift weapon.
His images were beamed across the globe and picked up by major newspapers. But after the awards ceremonies, the nightmares came.
"When I look back at my images, I can smell the fear and I can hear the screams. It happened in my country. Where I took the pictures, they are places that I normally go. So the images are a daily reality to my life," he says.
He adds the pain turned to anger then activism. "I was forced by circumstance. There was too much silence. The problems are there and I face them everyday. I see them everyday. But there is no one doing anything about it."
Mwangi organized photographic road shows to remind people of the horror that the political violence caused.
He says: "I believe in the power of visual art and so photography was my tool but it can only do so much. But in graffiti there is enough space to play around with images and words and pictures that don't exist."
He met up talented graffiti taggers working in Nairobi. At the time they were spraying images of Michael Jackson and Tupac. That has definitely changed.
On the white wall the image is coming together. It's an acerbic take on Michelangelo's "Creation of Adam."
Jomo Kenyatta and Daniel Arap Moi, past Kenyan presidents, reach out to touch a gaggle of Kenya's political brass. But instead of Michelangelo's angels, they are portrayed as vultures. "Axis of Evil" is sprayed in stark red writing above the group.
Despite decades of corruption scandals implicating leaders and politically motivated flare ups, Transparency International, an NGO that works to expose corruption in government and business, says that not one senior politician has been brought to justice in Kenya.
So the artists believe they are just drawing what Kenyans are already thinking.
"It is not like nobody knows what is happening," says Uhuru, "but I think the style we are using speaks a thousand words. We just don't want to have the same violence last time."
The group has been harassed by police. And at least one senior politician has tried to buy them off, says Mwangi.
They don't favor any political group; everyone is fair game, Mwamngi says. He wants to spark a ballot revolution.
"The power is in the vote. Four years ago we tried violence, It didn't work. So the power is in the vote. We want change. It can only come through the vote. And that is why we are doing the graffiti.
"Our whole idea is when you are going to work or when you are going home you see this big mural and you can have that conversation with yourself and you can ask yourself: 'are we that stupid, why do we still vote for these people?'"