Mexico City  - Public prosecutors suspect that some of the 24 men found murdered 10 days back near Mexico City were construction workers who were building a tunnel across the US border for the Sianloa drug cartel, it was reported Monday.

The workers were abducted from their homes in El Olivo, a poor suburb in western Mexico City on September 10. They were found dead two days later.

The previous week, police discovered a tunnel to transport drugs from Mexicali in Mexico to Calexico in the US state of California.

Public prosecutors were probing whether some workers had talked too much about their "special work" on the northern border. They were also investigating whether the workers were killed to prevent them from revealing the existence of other tunnels, the Mexican daily Milenio reported.

It was possible that some of those killed had nothing to do with the tunnel and were simply "in the wrong place at the wrong time," the report said.

The tunnel was 150 metres long with a diameter of 1.5 metres. It had lighting, ventilation and air conditioning, and cost an estimated 1 million dollars to build, the report said.

Authorities were also investigating construction projects in Huixquilucan, a town near Mexico City where the builders were active and in which large luxury residential compounds have been built in recent years.

The 24 bodies were found on September 12 in Ocoyoacac, just outside Mexico City and very close to Huixquilucan. All the men were shot through the head, a characteristic of organized crime killings.

More than 3,000 people have been slain this year in Mexico's drug cartel wars, despite military and federal police operations that have been in place for close to two years to combat drug crimes. (dpa)