Ten policemen were arrested on Saturday in the western state of Michoacan in connection with the murder of 12 federal police whose bodies were found piled next to a road, prosecutors said.
The men are being held for 40 days while the killings are investigated.
The preventative detention will allow investigators “to strengthen evidence that the men arrested on Sunday undertook criminal acts in support of the Michoacan ‘La Familia´ (drug cartel) and determine their responsibility for the murder of federal agents,” prosecutors said in a statement.
The bodies of 11 men and one woman working for the federal police were found stacked together on Tuesday, bearing signs of torture, police said.
Officials earlier suggested the killings might be linked to the powerful “La Familia” drug cartel, which operates in the region and is considered one of the most violent criminal gangs in Mexico.
Last weekend, “La Familia” launched a series of attacks against police posts in Michoacan that left four people dead, including three members of the security forces and one suspected cartel hit man.
President Felipe Calderon, who has waged a major crackdown on the drug cartels in Mexico, called those attacks “desperate and violent reactions.”
Michoacan -- Calderon’s home state -- has also seen violent clashes between rival drug cartels.
“La Familia,” which operates mainly in Michoacan, burst into the headlines in October 2006 when an armed commando linked to the cartel entered a bar and tossed five severed heads onto the dance floor.
Calderon has deployed 36,000 soldiers and federal police to the cities most affected by drug violence.
More than 7,700 people have been killed in drug violence in Mexico since 2008, according to government figures.