Updated

Mexican officials made a gruesome find Monday a northern border state -- at least 20 bodies buried in multiple secret graves, authorities said.

The Mexican army found the bodies of 19 men and one woman in 12 clandestine graves in the town of Puerto Palomas, Chihuahua, which is just north of Columbus, New Mexico, said Jorge González, Chihuahua's prosecutor.

The badly decomposed bodies had been buried between four and eight months ago, González said. Their cause of death was not known.

Earlier this month, the bodies of 18 men who were kidnapped in Acapulco where they had gone on vacation were found in a mass grave outside the resort city. An alleged drug trafficker arrested last week in Mexico City told police he ordered the killings after mistaking the men for members of a rival cartel.

Also in Chihuahua state, gunmen in two trucks chased and killed the newly appointed female police chief of the town of Meoqui on Monday. Hermila Garcáa Quiñones was driving to work when the attackers opened fire on her car, said Carlos González, a spokesman for the state attorney general's office.

García became police chief Oct. 9 after a new mayor took office. García, a former prosecutor, had never been a police chief before and authorities said she was the first woman to hold that post in Meoqui.

No one was arrested and no suspects were named.

The grisly discovery comes just days after Mexican police made the high-profile arrest of alleged drug lord Arturo Gallegos Castrellón, the purported leader of the notorious gang the Aztecas.

Chihuahua state, across the border from New Mexico and Texas, is one of the states most affected by drug violence and has recently seen an increase in the number of women leading police departments after men rejected the jobs out of fear.

In Praxedis G. Guerrero, east of Ciudad Juárez, 20-year-old university student Marisol Valles Garcia was named police chief in October. Valles Garcia's predecessor was shot to death in July 2009 and the town had no police chief until the young woman accepted the job.

Two other municipalities near Ciudad Juárez, which is sits across the border from El Paso, Texas, have also sworn in women as police chiefs.

In the Pacific coast state of Michoacán, gunmen killed the deputy police chief of the port city of Lázaro Cardenas, authorities said. Joaquín García Gómez was at a gas station when assailants attacked him Sunday night, state prosecutors said in a statement Monday.

Police commanders, mayors and other leaders have increasingly become targets of drug gangs that are seeking to control territory for their operations, particularly in northern areas. More than 28,000 people have died in drug-related violence since President Felipe Calderón ordered a crackdown on gangs when he took office in December 2006.

On Monday, the Inter-American Press Association urged Calderón in a letter signed by hundreds of newspaper readers from throughout the Americas to find those responsible for the killing of a newspaper Mexican reporter.

The group asked Calderón to help move forward the investigation into the killing of Armando Rodríguez, who was shot in front of his daughter in Ciudad Juárez two years ago.

Based on reporting by the Associated Press.

Follow us on twitter.com/foxnewslatino
Like us at facebook.com/foxnewslatino