Last month, in San Luis Potosi state, the bound bodies of four people were found in the burned-out wreckage of a helicopter, along with signs indicating they were killed by a drug gang.

    In the southern state of Guerrero, authorities said Friday they had found six bodies with bullet wounds and two heads nearby.

    The Guerrero state prosecutor's office said the remains were found near a burned out and shot up vehicle in the municipality of Quechultenango.

    Mexico President Andrés Manuel López Obrador continues to face stubbornly high rates of violence more than midway through his 6-year term. The president has emphasized attacking violence with social programs rather than head-on confrontations with the country's powerful drug cartels.

    "I am absolutely convinced that you can't confront violence with violence, coercive measures are not enough, that is the conservative, authoritarian vision," López Obrador said last month.