Sitting very still, hands folded and with a soft voice, Jean-Bosco Rurangirwa relives the trauma of seeing his family hacked to death as they sheltered with thousands of others in a church.
Twenty years ago, it is said that one person died every 10 seconds over a period of 100 days as genocidal government troops joined by armed militia swept through the country.
In all at least 800,000 people, mostly ethnic Tutsis, were murdered in the slaughter that started on April 7, 1994. Countless others were raped or maimed, and trauma is said to affect a third of the population.
"Sometimes I still feel human, but other times I feel crazy," said Rurangirwa, whose family died at Nyamata church, some 35 kilometres (20 miles) from Rwanda's capital Kigali.
"When you've seen so many dead bodies - I saw about 200, including my wife, my father, my son and my daughter - you lose your mind. You become crazy."
"That's from where they threw the grenades," recounted Rurangirwa, pointing to the many holes in a tin ceiling that cast a slanting kaleidoscopic light across the heaps of old clothes, broken glasses, loose change and the odd pen left behind.
He and around 50 others managed to escape Nyamata church at night after hiding himself under the benches and the dead bodies of his family, friends and neighbours.
But they were picked off on the way by the Interahamwe, marauding gangs of civilians from the Hutu ethnic group who were whipped up with hate speech and given crude weapons to kill.
The daughter he escaped with - his only surviving child - was also murdered, leaving Rurangirwa alone and fleeing to neighbouring Burundi for safety.
Two decades later Rurangirwa has remarried and has four children, but admits he struggles to come to terms with the brutality.
"When you've seen the bodies of your children lying next to your wife, there are just no words."
Naason Munyandamutsa, deputy director of Rwanda's Institute of Research and Dialogue for Peace, arrived in 1994 as the country's only psychiatrist.
"We didn't really know how to deal with this. In our culture, we didn't have a language to speak to our communities about trauma," he says.
With only "ihamamuka", a word used to describe the paralyzing fear of over-beaten cows, and "ihungabana", a crippling distress that can leave you breathless, psychiatrists had to invent new terms to help what a survey showed was 26 percent of the population suffering post-traumatic stress disorder.
Munyandamutsa says that Rwanda also had to create a national health policy from scratch. From one psychiatrist two decades ago, now there is one in every district.
But it's still not enough.
"There's a tiny percentage that have managed to get therapy," he says, while "the problem has become even more complex".
Many live their day-to-day lives with a sense of calm, in a country where expressions of anger have been muted so as not to tip the balance towards hatred and the danger that brings.
"People are scared of speaking as before, speaking killed, and no one knows how to speak the language of healing," he says.
Coffins at the Nyamata Church Genocide memorial in Nyamata, Rwanda. Photo / AFP
For Rurangirwa, who has forgiven some of his fellow villagers who admitted to being in the gang that killed his family, the fear of another genocide and the images burnt into his mind of the church will always remain.
"There are some things that can't be forgotten. As a human being, there are certain things that you can't let go of or talk about," he says.
But it is around April each year that the real rawness of what happened here can be glimpsed.
"What we see in times of commemoration is some people stunned to silence, falling over, having epileptic fits or crying," says Munyandamutsa, who sees these actions as a cry for help.
"Sometimes you have to shout to make the deaf hear," he says.
Rurangirwa is still struck down by fear when he hears news of Hutu militias launching attacks in neighbouring Democratic of Congo, and sees killers from twenty years ago who have been released from prison and greet him in the street.
But for the most part, "life has restarted... that hurt has faded", he says.
For Mundyamutsa, who witnessed bullet-riddled bodies in hospitals and listened to the deep trauma of children who saw their parents killed, Rwanda's transformation has been huge.
"It was night at that time, a kind of darkness, a deep one," he says.
"Now the darkness hasn't gone totally, but we have light. And we can open the door, and the window, to be able to look to the future."