In 2014, after After the disappearance of 43 normal students from Ayotzinapa in Mexico, Silván and other CentroGeo professionals joined the scientific advisory board of the case. During the search for the students, different civil groups and government brigades detected dozens of illegal graves. In less than 10 months, the Mexican Attorney General’s Office counted 60 sites and 129 bodies in the state of Guerrero. As a result of the raids, 300 illegal graves were discovered. Since then, the number of clandestine graves has only grown.
No one anticipated the magnitude of this horror. the report“In search between pain and hope: Findings of clandestine graves in Mexico 2020-2022”, explains with newspaper data that in those two years, 1,134 clandestine graves were registered, with 2,314 bodies and 2,242 remains. In proportional terms, Colima reported the highest rate of illegal graves, with 10 per 100,000 inhabitants. Sonora, Guanajuato, Guerrero, Sinaloa and Zacatecas followed.
By number of cases, Guanajuato, Sonora and Guerrero stand out. These three entities concentrate 42 percent of the records. By April 2023, a journalistic investigation by Quinto Elemento Lab reported that the number of illegal burials reached 5,696 clandestine graves, and that more than half of them were detected during the current federal administration.
Using your field of study, remote sensingJosé Luis Silván uses images captured with satellites, drones or airplanes, from which he extracts geospatial information using knowledge of the physics of light, mathematics and programming. Multispectral and hyperspectral images capture subsurface information using sensors that record wavelengths of light imperceptible to the human eye, making them useful for search.
In 2016, during a first study carried out by CentroGeo researchers, they simulated burials with pig corpses to evaluate the potential of using hyperspectral cameras in searches and to know what information from the sensors was useful to them. Mexican researchers knew from research conducted in other countries that successful detection with these techniques depends, in part, on being able to recognize how corpses (and their spectral images) change in different soils and climates.
The experiment was carried out on rented land in the state of Morelos. There they buried seven animals and evaluated the light reflected by the ground at different wavelengths for six months. They concluded that a hyperspectral camera, which provides more than a hundred layers of data, has the potential to detect clandestine burials, although the technique is only effective three months after the burial. They tried to manage the acquisition of a camera and a drone (valued at 5 million pesos) through the National Search Commission, but they were unsuccessful.