According to officials, 30 Mexican Marines were arrested in 2014 for the disappearance of an unspecified number of people in northeastern Tamaulipas.
Prosecutors say the victims went missing when the Marines were deployed in the border city of Nueboloredo.
Since 2006, about 85,000 people have disappeared in Mexico. When the government begins a war with drug traffickers.
Criminal groups are most often behind, but security forces have also been blamed.
This is the largest detention of military personnel associated with the disappearance of recent years and the blow to the Mexican Navy, which is considered the country’s most reliable security force.
The Navy said in a statement last Friday that Marines had been handed over to the Attorney General’s office “according to arrest warrants … on charges of enforced disappearances.”
Details have not been released.
Tamaulipas, one of Mexico’s most violent states, has the highest percentage of disappearances in the country. Most disappearances occur on roads leading to the United States.
Enforced disappearances are rarely fully investigated in Mexico, and almost all cases remain unresolved. Thousands of victims are either unidentified in morgues across the country or buried in secret tombs.
According to activists, corrupt security forces are suspected of being involved in many of the disappearances to cover up fatal misconduct or to collude with criminal gangs detaining victims for ransom.
In one of the hottest cases, 43 students disappeared in southern Guerrero in 2014.. Prosecutors in the case said the students were handed over to a criminal organization by corrupt local police, who killed them and burned their bodies.