The prisoner, who comes from the Rarámuri indigenous group, says the trouble began at a traditional festival that involved downing considerable amounts of the corn-based spirit called tesgüino.

"My cousin arrived at 4am with a caliber 22 gun and began walking towards me," he recalled, asking that his name not be used. "When I felt the bullets inside my body and all the desperation, I turned around and placed a bullet in his forehead. My cousin fell down onto the flames and I pulled him away so he would not get burned. I told another cousin to give word to the sheriff."

The self-confessed killer is now serving his sentence in Mexico's only prison which is populated exclusively by indigenous inmates.

Walking into the Guachochi jail — which is located in the mountains of the northern state of Chihuahua — turns upside down most preconceived notions of Mexican prisons. There are no tell tale signs of overcrowding, domination by internal mafias, endemic corruption, or the underclass of prisoners incarcerated for trivial crimes, that numerous reports have said are the norm for most Mexican prisons.

Instead Guachochi has empty beds and a reputation for being filled with inmates convicted of serious crimes who neither consume drugs nor seek to bribe guards. All of the 253 prisoners are indigenous, most of them with Rarámuri roots, but it is also possible to find primas, tepehuanes, and guarijíos — Chihuahua's other three ethnic groups.

Prison director Juan Martín González says he is proud of the prison, that opened in January 2015, and which he says is mostly populated by people accused or convicted of murder, rape, and assault.

"Most of them did this under the influence of alcohol," he said, adding that much of the violence in the area is also a byproduct of the war between drug cartels.

Prisoners wait patiently inside a cell. (Photo by Nadia del Pozo/VICE News)

Indigenous communities in these mountains employ their own traditional justice systems for minor offences, but serious crimes such as homicide and sexual assault tend to be accompanied by pressure from local leaders on alleged perpetrators to go and give themselves up.

That's why Guachochi's authorities estimate 50 percent of the inmates have handed themselves in, some walking for hours to get to the prison gates to confess. They say it has also contributed to a recidivism rate of just two percent.

González, the prison director, walks casually around the facility. He passes through the kitchen, the workshop, the bakery, and a library insisting that here nobody takes crack or other common cheap prison drugs, and that there are no records of suicide or sexual abuse.

Inmates are distributed in one of the two stories, in cells of ten bunk beds each. They would be unable to buy luxuries and commodities even if they wished to, because they are poor.

At lunchtime, the prisoners make an organized line in the jail's main courtyard which also hosts volleyball and basketball games throughout the day. Most of them wear a gray uniform and, despite the heat, some wear blue raincoats on top. Everything feels calm.

Inmates practice traditional Rarámuri wrestling during their free time. (Photo by Felipe Luna/VICE News)

It is a far cry from the situation described in a 2015 report on the penitentiary system by Mexico's national human rights watchdog that found half of all facilities are ruled by inmates in collusion with authorities. The report also highlighted the inability of prison guards to deal with riots, and the dozens who die every year behind bars.

The most recent high profile mutiny took place in February, inside the Topo Chico jail in Monterrey. A confrontation between two leaders of the Zetas cartel left 49 people dead.

The ensuing investigation found saunas, marijuana, flat screen televisions, king size beds, an aquarium, and a bar inside the prison. It also revealed that of the Topo Chico's 900 prison guards, 300 had failed so-called trust tests.

Around 52 percent of prisons in Mexico are overcrowded and most inmates face theft charges. Three out of every five prisoners are in jail for stealing less than $595, while one fourth are there for stealing less than $108, according to a recent report by the Mexico City based think tank CIDE.

The report also highlights the terrible conditions in which inmates live. Most prisoners do not have enough water, they don't receive proper medical attention, the food they eat has no nutritional value, and they don't feel safe. But Guachochi claims to have none of these problems.

Once the lunch hour is over, the inmates resume their preparations for Holy Week, the most important festival for the indigenous people of Chihuahua, when they commemorate Christ's death and resurrection. This year, a non-profit organization gave them guitars and violins so they could play their traditional music at the fiestas believed to help heal and reorganize the world.

Rosendo Arazola, who is imprisoned in Guachochi for murder, said this was all a far cry from life in the two other non-indigenous prisons in the state where he also spent time.

The 29-year-old member of the Tepehuán indigenous group added that indigenous inmates are also often humiliated and discriminated against in other prisons. He also claimed "here there are no cartels."

This is certainly not true in the mountain communities where most of the inmates come from.

In recent years, the indigenous peoples of the mountains range have witnessed how opium poppy plantations have taken over their lands. Working for cartels and leaving their home behind is sometimes necessary to save their lives.

Some communities stopped their traditional celebrations out of fear of organized crime, and some prisoners in Guachochi recognize that the backdrop of the drug wars is not so easy to escape.

One inmate told how he had killed a man who shot him twice when he was drunk, drugged, and also carrying a weapon. Now, he said, he was dreaming of returning to his community.