Prosecutors in western Mexico confirmed this week the discovery of hundreds of clothing items and bone fragments by a group of people searching for relatives at a previously known cartel training site, exposing major shortcomings in the original investigation.

But the discovery in the state of Jalisco was hardly the first such gruesome discovery. Mexico’s official registry counts more than 120,000 disappeared people. The discovery of such places has accelerated in the past 15 years as more relatives of the missing do the work the government often won’t to search for their missing loved ones.

In this case, it was the Jalisco Search Warriors group checking out a ranch in Teuchitlan, about 37 miles (60 kilometers) from Guadalajara that was found by National Guard troops last September.

At that time, authorities said 10 people were arrested, two hostages were freed and a body was found. They described it as a cartel training site. The state prosecutor’s office went in with a backhoe, dogs and devices to find inconsistencies in the ground, but then the investigation inexplicably stalled.

The search group had gone there after receiving an anonymous call, said leader Indira Navarro.

“This ranch served as a training site and even though it sounds awful, really harsh, for extermination,” Navarro said.

The site is only the latest in a troubling history of such places in Mexico. Drug cartels have used these often remote locations to make their victims disappear.

When The Associated Press visited a site near Nuevo Laredo, across the border from Texas, in 2022, a room in a small abandoned house had been converted into a crematorium. When investigators had first arrived the floor was covered with 20 inches (50 centimeters) of bone fragments and ash and more bones were scattered across the ranch.

Here’s a look at several other cases that have unnerved Mexicans:

In 2009, Santiago Meza confessed to authorities that he had made 150 to 300 bodies disappear for his drug lord boss by dissolving them in lye.

Meza used big oil drums and then buried the remaining bones or dumped them in streams. He was dubbed the “Pozolero,” or the one who makes pozole, a Mexican stew. He said he wasn’t the only one who did it.

Mexico hadn't been accustomed to finding large clandestine graves. That changed in 2011, when nearly 200 bodies were found in graves on the outskirts of San Fernando, south of Brownsville, Texas. It was the same town where a year before 72 migrants had been killed on a ranch.

Authorities struggled to identify and process all of the victims.

Officials said most of the bodies found in and around San Fernando belonged to Central American migrants kidnapped off buses and killed by the Zetas. Some were offered the chance to live and join the gang — if they proved their worth by fighting other innocent passengers with sledgehammers.

In 2017, the Colegio de México shared its investigation that determined the Piedras Negras jail, across the border from Eagle Pass, Texas was a base for the Zetas cartel.

The investigators said that as many as 20 people had the job of dispatching the cartel’s victims in barrels of diesel fuel.

Victims were sometimes shot on site or bludgeoned to death and dismembered.

Local media around Matamoros began to talk about this site in Mexico’s far northeast corner, where the Rio Grande dumps into the Gulf Mexico, in 2016. But it was years before authorities did anything.

When Tamaulipas Search Commissioner Jorge Macías visited for the first time he saw “pelvic bones, craniums, femurs, everything thrown there … I said to myself ‘it can’t be,’” he told the AP in 2021.

By 2022, authorities had recovered some 1,100 pounds (500 kilograms) of bones at La Bartolina. They had identified at least 15 “extermination sites” in the state with La Bartolina being the largest. Federal investigators are still working there.