Vigilantes fighting Mexico's drugs cartels are operating an unofficial, illegal jail where they have locked up gang members for "crimes" including murder. The discovery of the jail, high in the Sierra Madre mountains, provides new evidence of how far the government's complicity with the cartels and its failure to stop the violence has driven people to take the law into their own hands.
In this area of Jalisco state in Western Mexico, people have been terrorised by the drug gangs' gunmen for decades. They see the establishment of their prison as an important symbol of their "revolution" against organised crime.
The Mexican government's writ doesn't run here; the vigilantes are in absolute control. The dozen inmates hang out of the barred windows of a converted municipal building guarded by vigilantes armed with shotguns and dressed in matching green t-shirts and trousers. Escape is impossible, there is only one road off the mountain and to get down it you have to pass through a vigilante checkpoint.
Most of the prisoners have been incarcerated after being simply snatched off the streets, although some are tried by kangaroo courts of local "elders" who adjudicate on anything from civil land disputes to crimes including rape and murder.
Leonardo, who is 22 but seems much younger, is typical of the prisoners. His horrifying history of violence for the Knights Templar drug cartel includes committing 19 murders over three years. He says he has already been in the prison for a year.
Leonardo says he had tried to run away from the cartel but was tracked down and betrayed to the vigilantes.
"They planted three bags of Mota (Marijuana) on me and that was my problem.....they used a girl to plant the drugs, and that girl they have since killed," he tells me, his head bobbing and eyes shifting nervously from side to side.
"I don't want to talk about it in here, my integrity is in danger, my life is in danger," he adds.
Leonardo admits everything. He says he was under the control of the cartel and could do nothing to avoid their demands to carry our murders.
"What's the point of lying to you? It is true they arrested me with evidence and all. When they caught me I had drugs, shotguns and other weapons," he adds.
While the cartels usually pay hit-men, it seems Leonardo murdered for nothing, simply to stay alive himself. It was a question of kill or be killed.
Miguel, a self-styled vigilante social worker who is trying to rehabilitate the inmates, says Leonardo's story is typical. They become contaminated and it becomes natural for them to kill.
"We have investigated him. His life is a life of poverty. It is a very miserable life, very, very poor. Their way of paying him was the life of another in exchange for his life," he continues.
The inmates are not all cartel gang members. Some have simply been identified as anti-social trouble makers and criminals.
Certainly this prison is unsuitable for proper rehabilitation or, indeed, proper punishment, but the vigilantes are unrepentant. Locking these men up in cells with only mats on the floor and almost no recreational or exercise time is a fitting return for the fear they have brought to their communities. They want this message to get out.
Our guide, "Renee", was an illegal in the USA before being deported. He paints a horrific picture of life in the gang-controlled parts of the Sierra Made before the vigilantes started to clean up the area.
"After eight o'clock at night you couldn't go out in your town. A car would drive by and you would look at it. It would turn round and the guy would say 'what you looking at?' You say 'Nothing.' He takes a gun out and shoots you," he says.
Sometimes you would get a phone call. "The criminals come to you and say 'hey, you are Renee?', and I say yes 'I am Renee, what happened?' And they say 'you have daughter?' and I say 'yes I have daughter.'
"They say: 'Your daughter is...' they say the name, and they say 'I want your daughter in the hotel at this hour, if you bring me your daughter right here... because if he doesn't... then I will kill all your family. Then you have to take daughter, and take her to the hotel.
"People did that, it was really, really bad. All the people in the city were scared, they were really scared. Nobody tried to talk and they'd ask 'Hey what happened to your daughter?' and he'd say 'I don't know'. But the people know that he'd taken the daughter ... to the hotel for the criminal and they disappear."
The fate of Mexico's estimated 27,000 "Disappeared" has been highlighted by the latest developments in the case of forty-three students from Guerrero in the south-west of the country, who were apparently rounded up by the police and handed over to the Guerreros Unidos cartel. Most people believe they have been massacred, but the search for them continues to produce new, gruesome discoveries
In the hills above the town of Iguala a group of families gather to start a search for new mass graves. They have already found three.
Above them vultures swoop and turn in the deep blue skies. Dogs had started turning up in nearby villages with human body parts. The families of the local "Disappeared" know they are in the right place.
After about 20 minutes another grave is identified and they madly hack at the earth before a local forensics officer asks them to stop.
In the tearful exchange that follows the family members give a sense of their anger and outrage. They berate the officer for the failings of the government, for the rampant corruption and the overarching power of the drug gangs.
"Young man, you get to finish your shift then you get to go. We can't, we have to stay here, we can't move from here," a woman shouts through her tears pointing at the grave.
"We demand that the government come and take them out. That they stop treating us like idiots, because that is what they have treated us like. People's family members are here, whether it be a brother or sister or child, they have to come and get them out."
There is plenty of anecdotal evidence for the close relationship between the arms of the Mexican government and the cartels, but few concrete facts. In Iguala, for example, local villagers say the trucks bringing the latest victims of the violence passed their houses along roads which had been closed by the police.
However, in Mexico City I was introduced to a man prepared to admit his involvement in mass murder while part of the army.
Carlos (not his real name) is an assassin. He says he has killed between 500 and 900 people (he is unsure of the exact number) during 25 years working for the drug cartels, politicians and the military.
He says that the network of cartel power is so entrenched in society and powered by so much money that it is unstoppable. The police are often involved in the planning and execution of his hits.
"On some occasions we have to go to places where weapons are not allowed and then they (police) meet us. They take us to a hotel and they provide all the weapons that we may need, money and everything so that one can do the job one has to do," he told me.
Carlos is certain the 43 students are already dead and cites a chilling example from his own experience.
"Some protestors came. We let them in and then we closed the road, we closed the entrance, the army came and collected them all. Then street sweeper machines went past. They opened the road again, as if nothing had happened.
"The students are dead, it is more convenient. For kidnapping you get 160 years, for killing its 35. It's a huge difference don't you think?"
The dreadful but inevitable conclusion of what Carlos says is that with the profits from drugs so high, the money distributed amongst the most powerful and influential and a financially poor population inured by so many years of violence, the vigilantes may be Mexico's only hope of achieving any kind of peace at all.
For a US audience - Stuart Ramsay's reports from Mexico can be seen on Sky News which is available on Apple TV, Roku and other connected TV applications.