A group of volunteers searching for their missing relatives first received a tip last week about a mass grave hidden in western Mexico.
When they arrived at an abandoned ranch outside La Estanzuela, a small rural village outside Guadalajara, the Mexican authorities said, they discovered three underground cremation ovens, burned human remains, hundreds of bone shards and discarded personal items, along with figurines of Santa Muerte — the Holy Death.
In statements, the authorities said they later found 96 shell casings of various calibers and metal gripping rings at the ranch. By last Friday, the discovery was dominating local newspapers and TV reports, and the search group was referring to the site as an “extermination camp.”
It is unclear how many people died on the site, and none of remains have been identified. The authorities have yet to say who operated the camp, what crimes were committed there and for how long. But this week, the Attorney General’s Office took over the investigation at the request of President Claudia Sheinbaum.
Photos taken by the authorities and by the volunteer group, Searching Warriors of Jalisco, at the abandoned ranch showed more than 200 shoes piled together and heaps of other personal items: a blue summer dress, a small pink backpack, notebooks, pieces of underwear. The more than 700 personal items were a chilling hint about the number of people who may have died there.
In a country seemingly inured to episodes of brutal violence from drug cartels, where clandestine graves emerge every month, the images shocked Mexicans and prompted outraged human rights groups to demand that the government put an end to the violence that has ravaged the nation for years.
“We immediately connected them with Nazi concentration camps,” said Eduardo Guerrero, a security analyst based in Mexico City. “The number of the victims that presumably could have been buried there is enormous, and it resurfaced the nightmarish reminder that Mexico is plagued with mass graves,” Mr. Guerrero added.
More than 120,000 people have been forcibly disappeared in Mexico since record-keeping began in 1962, according to official data. Human rights groups and collectives of volunteers in search of their missing relatives have warned that the number could be higher.
The discovery at the ranch comes at a time where Ms. Sheinbaum faces intense pressure from President Trump to crack down on organized crime in order to avoid tariffs on exports to the United States and even possible U.S. military intervention to hunt down cartel members.
Partly because of Mr. Trump’s threats, Ms. Sheinbaum has shifted security issues back to the center of her agenda and has taken a more aggressive approach to fighting crime than her predecessor, experts and analysts say. But her government faces significant challenges as she tackles the powerful criminal groups that control large areas of the country.
One of the most violent criminal organizations in Mexico, the Jalisco New Generation Cartel, which emerged in the early 2010s, is now a major producer and trafficker of synthetic drugs, particularly fentanyl and methamphetamine. The group, which operates in the state of Jalisco and across the country, has diversified into other criminal activities like illegal logging, human trafficking and extortion.
The authorities have said that the ranch could have been operated by the Jalisco cartel. The group’s dominance and its rapid expansion in recent years have coincided with a growing number of homicides, forced disappearances and discoveries of mass graves in Jalisco state.
Indira Navarro, leader of Searching Warriors of Jalisco, which found the site, said in interviews with local news media this week that several individuals had contacted the group to say that they had been recruited and trained at the site in the use of different weapons and torture techniques. But the ranch, they said, was also used as a killing site where criminals routinely disposed of their victims.
Ms. Navarro, who could not be reached for comment, told the news outlets that, according to the testimonies, young people from other states were recruited through false job offers posted on social media. Once they accepted the jobs, she said, they were summoned to a bus station in Guadalajara, the state capital, and from there they were taken to the ranch.
Ms. Navarro recounted that one young man had told her that the young recruits were at times forced to burn their victims as part of their training. If they objected to the orders of their trainers, the recruits were sometimes fed to wild animals, like lions, she said.
“This is not a horror film; this is our reality, and people should know about it,” Ms. Navarro, whose brother went missing nine years ago, said in an interview with a national radio show.
The New York Times could not independently verify the accounts.
The local authorities first located the ranch last September and found weapons, shell casings and bone fragments there, according to official reports, but further investigations were stopped for reasons that are unclear. During the same inspection, officials found and rescued two people who had been kidnapped and held at the ranch, and also discovered a body wrapped in plastic.
The state attorney general, Salvador González, has since told local news media that it had not been possible to search the entire ranch back in September “because there are a lot of hectares in the area.”
Ms. Sheinbaum suggested during a news conference this week that the local authorities might have been omissive in their initial investigation.
The attorney general “is correct in stating it is not credible that a situation of this nature would not have been known to the authorities of that municipality and the state,” she said. “But the first thing we have to do is investigate.”