(CNN) -- In recent days, Michoacan, the home state of President Felipe Calderon, has become a flashpoint of violence in Mexico's deadly war against drug cartels. Since Calderon went after the drug cartels shortly after coming into office in 2006, more than 10,000 people have died across Mexico, about 1,000 of them police.
In the latest incident, 12 bodies of federal police officers were found on the side of a remote highway, said Monte Alejandro Rubido Garcia, technical secretary for Mexico's national security council, at a news conference Tuesday. The bodies showed evidence of torture.
The officers were "ambushed while they were off duty by an armed group," Rubido said. One of the 12 officers was a woman.
The bodies were found in a pile near the town of La Huacana, he added.
Rubido said the slain officers had been doing "investigative work" in the city of Arteaga in Michoacan, one of the states most affected by the government's offensive against drug cartels.
Rubido announced the arrest of Francisco Javier Frias Lara, known as "El Chivo," in connection with the killings of the officers.
Frias is a member of La Familia Michoacana, one of the region's most powerful drug cartels, Rubido said.
Federal police around the country will redouble security measures for its agents, Rubido said.
The sudden spike in violence followed the arrest Saturday of Arnoldo Rueda Medina, who authorities described as a high-ranking member of La Familia Michoacana.
Cartel members first attacked the federal police station in Morelia to try to gain freedom for Rueda, authorities said. When that failed, the drug gangs attacked police installations in at least a half-dozen Michoacan cities. Coordinated attacks in eight cities over the weekend left three federal police officers and two soldiers dead.
It was the federal police who arrested Rueda, and the current spate of attacks appear aimed at them in revenge.
On Tuesday, two federal police officers were killed and four wounded in an ambush in Michoacan, the state-run Notimex news agency reported.
Also Tuesday, a federal police station in the Michoacan city of Maravatio was attacked, news reports said. There were no immediate reports of casualties.
A local Michoacan newspaper put the body count in recent days at 32.
La Familia Michoacana emerged in the 1990s as a conservative paramilitary group designed to insulate the state from the large drug cartels, said Bruce Bagley, a professor at the University of Miami and expert on drug trafficking.
But over the years, the group evolved into a drug trafficking operation itself, forging strategic alliances with warring cartels to raise its own profile.
This week's violence solidifies the cartel as a major and violent player in Mexico's drug wars, Bagley said.
"This represents the third evolution of the Familia Michoacana," he said.
Reprisals from drug cartels following major arrests have been reported before, but the intensity of these attacks in Michoacan are unprecedented.
La Familia Michoacana wants "to demonstrate that they have power and will not go away quietly into the night," Bagley said.
Video from the scene of the slain officers showed three signs, known as narcomensajes, left by the killers that stated the same thing: "So that you come for another. We will be waiting for you here."
But the state of Michoacan, on Mexico's southwest Pacific coast, is not alone in the wave of violence sweeping the country.
The border city of Ciudad Juarez set a record this weekend when its toll of drug-related deaths for the year topped 1,000, a distinction the Mexican city did not reach last year until September.
At this point last year, the violence-plagued city across the border from El Paso, Texas, had tallied 596 killings, El Universal newspaper said Tuesday, citing figures from the Chihuahua state attorney general's office.
Also in Chihuahua state, a mayor was shot and killed Tuesday morning while on his way to work. Ariel Meixequeiro had twice before temporarily left his post because he had been threatened by crime gangs, El Universal said.
CNN's Mariano Castillo contributed to this report.