Four of the victims were found in a car in the western city of Apatzingan, along with a message threatening the Zetas, a group of hitmen for the Gulf cartel.
The message was signed La Familia, a drug gang battling for territory in western Michoacan state.
Another slain man was found in the western port city of Lazaro Cardenas, also with a threatening message from La Familia to the Zetas.
A sixth man was found on a highway in the city of Morelia. He had been shot in the head three times and left with a T-shirt pulled over his head and his hands handcuffed behind his back. A seventh was found shot to death in the town of Tacambaro.
La Familia was once considered aligned with the powerful Gulf cartel, but it was named as a separate gang in a government list of most-wanted drug trafficking suspects released last month.
President Felipe Calderon's government has attributed fractures in the cartels to a military crackdown, saying the arrest of drug kingpins has set off internal battles for control that have led to Mexico's sharp surge in drug-related violence.





