Six Mexican police officers were murdered on Friday in the central state of Puebla which is ravaged by gangs active in drug trafficking, fuel theft and kidnapping, local officials said.
The five men and one woman belonged to a municipal force in Amozoc, about 150 kilometers (93 miles) from Mexico City.
State Security Secretary Jesus Morales said authorities found a tanker truck with an "illegal" cargo of fuel at the rural crime scene.
Two armed suspects were arrested, he said.
Puebla often sees clashes between police and criminal groups targeting the theft of fuel from pipelines belonging to state oil company Pemex.
In May, 119 police officers in Puebla were relieved of duty on suspicion of collusion with fuel thieves.
Mexico is struggling with a wave of violent crime with a record 25,000 people murdered last year.
More than 90 percent of violent crimes in the country go unpunished.