A clandestine grave containing two bodies was found by investigators in Mexico state, which surrounds the Federal District and forms part of the Mexico City metropolitan area, prosecutors said.
The grave was found in San Juan Yautepec, a community outside the city of Huixquilucan, on Monday, the Mexico state Attorney General's Office said.
The bodies had been buried about 200 meters (655 feet) from another clandestine grave discovered last Friday in San Juan Yautepec that contained five bodies, the AG's office said.
The grave was found by investigators from the Special Prosecutor's Office for Kidnappings and the forests around the community will be searched for additional remains and evidence, the AG's office said.
One of the victims found in the first mass grave had been kidnapped and his family paid ransom, Mexico state Attorney General Alfredo Castillo said last Friday.
The mass graves were found following the arrests of three suspects in connection with nine kidnappings in Mexico City and Mexico state.
The suspects identified the places where they buried eight bodies, but investigators had only been able to find seven bodies in three clandestine graves, the AG's office said.
An average of 49 kidnappings per day occurred in Mexico in 2011, marking a significant increase from the prior year, the Council for Law and Human Rights, or CLDH, said in a report released earlier this year.
A total of 17,889 kidnappings occurred in Mexico last year, up 32 percent from the 13,505 abductions registered in 2010, the non-governmental organization said.
The figures do not include "express kidnappings," in which a victim is held for only a few hours, the CLDH said.
Hundreds of express kidnappings occur in Mexico City daily, with taxi drivers usually assisting the criminals, the NGO said. EFE