First Posted: May 10, 2012 08:02 AM EDT

Police and forensic technicians stand near one of two cars containing the remains of ten people in the parking lot of the morgue in Guadalajara May 9, 2012.
Credit: Reuters/Alejandro Acosta (Photo : Reuters/Alejandro Acosta)

Police found the decapitated and dismembered bodies of 18 people near Mexico's second-largest city, Guadalajara, on Wednesday, in what appeared to be the latest atrocity by the country's most brutal drug cartel.

Thought to have been carried out by the Zetas gang, it was one of the biggest mass beheadings in the recent history of Mexico, where decapitations have become alarmingly common.

The bodies and heads were stuffed into two vehicles abandoned on the side of a highway in the small town of Ixtlahuacan de los Membrillos, said Tomas Coronado, chief prosecutor for the state of Jalisco.

Some of the bodies had been refrigerated before they were dumped, Coronado said.

A policeman at the scene in Ixtlahuacan said some victims had been so badly mutilated that officers could not determine whether they were male or female.

The officer said a note by the bodies was signed by the Zetas cartel, a criminal militia led by former Mexican soldiers and blamed for some of the worst atrocities in Mexico's drug war.

Guadalajara, known for its high-tech industry, mariachi bands and tequila, has been a strategic base for drug traffickers since the 1980s.

Violence has flared in the once-tranquil city as the Zetas moved in to challenge the smuggling turf of other gangs in western Mexico.

Soldiers arrested a high-ranking member of the powerful Sinaloa Cartel in the city in March, causing his supporters to block streets with 25 burning cars and trucks.

Ixtlahuacan de los Membrillos lies 18 miles south of the center of Guadalajara on the road to Lake Chapala, a site popular with foreign tourists and American retirees.

Attacks between the Zetas and their rivals have flared up across Mexico since the beginning of the year.

On Friday, nine corpses were hanged from a bridge in the border city of Nuevo Laredo just hours before 14 bodies were dismembered and shoved into garbage bags and ice boxes.

Five days of intense battles in western Sinaloa state last week also left 34 dead, adding to the body count in Mexico's drug war, which has killed more than 50,000 people in the past five years

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