Mexico City (CNN) -- Authorities located four new mass graves in northern Mexico over the weekend after the arrest of a suspect in the kidnapping and killings of bus passengers, the Mexican military said.
Sixteen bodies were discovered in the clandestine graves in San Fernando, in the state of Tamaulipas, which borders Texas. The most recent find brings to 88 the total number of bodies recovered from mass graves in the area.
The military announced Sunday that it had captured Armando Cesar Morales Uscanga the day before in San Fernando.
The suspect admitted his participation in the kidnapping and killings of bus passengers on two separate days in March, the military said.
Morales provided information that led to the discovery of the other four graves, the military said.
Along with his arrest, the military seized an assault rifle, nearly $3,000 and more than 20,000 pesos.
Authorities began finding the graves last week during an investigation into a report of the kidnapping of passengers from a bus in late March. The investigation led them to San Fernando, the same place where in August of last year, the bodies of 72 immigrants were found at a ranch.
This time, authorities arrested 11 suspects -- not including Morales -- and rescued five hostages, the state attorney general's office said.
Tamaulipas is one of Mexico's most active states when it comes to drug trafficking. The Gulf cartel and the Zetas cartel operate in the state and have strongholds there.
The Zetas have been blamed for the killings of the 72 migrants found in San Fernando last year.