Federal authorities have found the bodies of nine of 35 people who were reported missing in Nuevo Laredo, Tamaulipas, between February and May.
The United Nations said on May 30 that there were “strong indications” that federal security forces were responsible for the disappearance of 23 persons.
But the federal Attorney General’s office (PGR) has now turned the focus of its investigation on to the Zetas drug cartel and suspects that the organization’s leader, Juan Gerardo Treviño Chávez, known as El Huevo, is behind the disappearances.
Members of cartel criminal cells who specialize in carrying out enforced disappearances are suspected of committing the crimes while wearing fake navy uniforms.
PGR personnel located the nine bodies at different locations in the northern border city and autopsies confirmed that the victims had been executed, presumably via gunshots to their heads.
Authorities also found a woman who was abducted but not killed. She said she had been let go by a criminal group.
The enforced disappearance investigation unit of the PGR has opened a total of 26 files in relation to the 35 missing persons. Four of the victims are women and five are minors.
Since the first disappearances occurred in February, victims’ family members accused navy personnel of carrying out the kidnappings. There are also claims that the real number of victims is higher than the 35 cases officially reported.
The Nuevo Laredo Human Rights Committee said it has documented 57 cases of disappearances in which the navy was allegedly involved.
Victims’ family members have held a series of protests to demand thorough investigations and last month demanded that federal authorities search the naval barracks in Nuevo Laredo
PGR personnel have now inspected naval facilities in the border city but they didn’t uncover any evidence suggesting that marines were involved in the disappearances.
However, the federal agency has not yet interviewed navy personnel who were transferred to Mexico City from Tamaulipas while the investigation takes place.
As three PGR officers and seven experts who are contributing to the investigation left naval facilities in Nuevo Laredo Monday, they were attacked by armed members of the Zetas cartel, adding further credence to authorities’ suspicion that the criminal group was involved in the disappearances.
Soldiers and Federal Police officers who were guarding the PGR personnel returned fire and a lengthy gun battle followed, splintering into confrontations across several neighborhoods.
The newspaper El Universal reported that one soldier and four civilians not involved in the confrontations received non-fatal gun wounds. Among the victims was the driver of a city bus.
Nuevo Laredo residents posted videos of the gun battles — which took place in close proximity to shopping centers and restaurants — to social media, showing witnesses in a state of terror and some of them getting out of their cars and throwing themselves to the ground to take shelter.
Officials said that personnel working for the PGR’s enforced disappearance investigation unit as well as Federal Police and criminal experts previously came under attack on June 12.
Following Monday’s incident, the head of the PGR’s missing persons search unit said in a media interview that evidence was mounting that organized crime rather than the navy is responsible for the series of abductions.
“Now with the progress [in the investigation], with the direct attacks, we are corroborating the involvement of organized crime, wearing uniforms similar to those the navy uses, in the disappearance of the  persons,” Abel Galván said.