Authorities say the bodies of 11 people have been found dumped along the highway in the southern state of Guerrero in what appears to be a series of drug-related killings.
The Guerrero state attorney general's office says the bodies were found early on Sunday, along with messages believed to be from a drug gang.
The 11 people had all been shot once in the head and bore signs of torture.
The bodies were discovered near Guerrero's border with Michoacan state, about 300 kilometres from the popular Pacific beach resort of Acapulco. Authorities were working to identify the victims.