Authorities in western Mexico have found the tortured bodies of eight men, heaped in a pile on a roadside.
The bodies were found in Michoacan state on Thursday. Authorities say the victims all had gunshot wounds to the head. Michoacan is the home state of Mexican President Felipe Calderon and has been the site of bloody drug-related violence. It is the base of the drug cartel known as La Familia.
Meanwhile, authorities have arrested 16 municipal police officers accused of protecting the drug gang hitmen behind a massacre in Tamaulipas state, near the U.S. border.
Mexican officials say as many as 126 bodies have been discovered in mass graves near a ranch in Tamaulipas in recent days. They say the Zetas drug gang was behind the massacre and have arrested 17 members of the gang so far.
Migrants trying to reach the United States often cross through Tamaulipas. The state is where 72 Central American migrants were found shot to death last August. The Zetas have been blamed for that massacre as well.
Drug-related killings have claimed at least 35,000 lives since 2006, when President Calderon took office and launched an offensive against the cartels.
The Zetas began as a Mexican military unit that defected and began working with the Gulf cartel, based in Juarez, Mexico, across the Rio Grande river from the U.S. city of El Paso, Texas. The Zetas split from the Gulf cartel last year. The two groups are now fierce rivals.