Mexican prosecutors have arrested the mayor of a town in the troubled western state of Michoacán on suspicion of collaborating with a violent drug gang, according to the Associated Press.

The state government of Michoacán said in a statement it had detained Uriel Chavez, the mayor of Apatzingán, a city that has been a major stronghold of the Knights Templar, the AP reported.

Michoacán state prosecutors said Chavez had aided suspected members of the drug gang in extorting members of the city council to the tune of 20,000 pesos, or $1,500, monthly to help the gang purchase weapons, according to the AP.

The meeting was held in January 2012, when the cartel was at the height of its power, according to prosecutors, the AP reported. The "self-defense" vigilante movement that sprang up last year to fight the cartel had long claimed the Knights Templar controlled, or extorted money from, municipal governments in the western, largely agricultural state.

Mexican President Enrique Peña Nieto pledged to restore order when he took office in December 2012, the AP reported.

Mexico has been racked by drug-related violence in recent years and more than 85,000 people have died in killings linked to drug gang violence since the end of 2006, according to the AP.

The Knights Templar has openly defied the government in Michoacán, and at the start of this year, federal forces began working with local vigilante groups in an effort to crush the cartel, the AP reported.

Since then, the government has killed or captured most of the senior leadership of the Knights Templar, though the face of the gang, Servando Gomez, remains at large, according to the AP.

The Knights emerged from a split in another cartel in Michoacán, known as La Familia, and have controlled large swaths of the restive mountainous state in recent years, extorting farmers and local businesses and even diversifying away from drug trafficking to industries such as mining, the AP reported.