Volunteer searchers in northern Mexico have discovered 11 bodies in clandestine burial sites just a few miles from the U.S. border, according to authorities.

The government of Sonora state announced late Monday that the bodies included nine men and two women. Clothing and other personal belongings were collected.

Sonora has been locked in a bloody turf war between competing Sinaloa cartels and gangs linked to fugitive drug lord Rafael Caro Quintero.

Investigators used backhoes to excavate a series of pits on Sunday and Monday, many holding several bodies in San Luis Rio Colorado, across the border from Yuma, Arizona, per ABC News.

The bodies were "badly decomposed," according to the state prosecutor's office, and remains will be compared with DNA samples and fingerprints in a Forensic Scientific Intelligence Laboratory for identification.

Authorities were led to the pits in a stretch of desert near a garbage dump by volunteer search teams made up of relatives of the missing. In many parts of Mexico, relatives of the disappeared must conduct their own searches because police are unable or unwilling to do so.

According to government data, around 98,356 are missing in Mexico. The majority of them are alleged to have been murdered by drug cartels, whose remains were dumped in shallow graves, burned, or dissolved.

Even the bodies that have been discovered have proven difficult for the officials to identify. A total of 52,000 people are awaiting identification.

'Pelvis, Skulls, Femurs, Everything Just Lying There' -Search Commission Chief

Disappearances are seen as the ideal crime because there is no crime without a corpse; and the cartels are experts at making sure no one finds the body.

Head of the Tamaulipas state search commission, Jorge Macías said that if a criminal group has total control of an area, they do what officials call "kitchens," since they feel comfortable burning bodies openly.

However, in areas that are not theirs and "where the other side could easily see the smoke," according to Macías, those cartel groups dig graves, per CBS News.

In 2009, a member of the Tijuana cartel confessed to "cooking" 300 victims in caustic lye on the other end of the border.

A report eight years later from a public university investigation center revealed that what was officially a jail in the border city of Piedras Negras was in fact a Zetas command center and crematorium.

Another border setting near the mouth of the Rio Grande, known as "the dungeon," in territory controlled by the Gulf cartel was perhaps the largest of these sites.

Macías is still shaken by the memories. The first time he went, Macías witnessed, "pelvis, skulls, femurs, everything just lying there" and he said to himself, "It can't be."

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Authorities Discover 15 'Extermination Sites' In Mexico

Fifteen "extermination sites" have been found, according to the Tamaulipas State Forensic Service. There are also graveyards.

In 2010, graves containing 191 bodies were discovered on one of the main migrant routes from Tamaulipas to the border. In Guerrero, Mexico's southern state, 43 students vanished in 2014. Only three of the burnt bones have been recognized.

Most of the extermination sites were discovered by family members who followed up on leads with or without the support and protection of authorities. These search groups exist in almost every state.

The discovery brings both hope and pain to the families.

Said a woman who has been looking for her husband since 2014, as well as two brothers who went missing afterward, "It brings together a lot of emotions."

Like thousands of other relatives across Mexico, she has dedicated her life to finding her loved ones. Finding a site makes you happy, but when you see things the way they are, "you nosedive," the woman said.

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This article is owned by Latin Post.

Written by: Jess Smith

WATCH: Mexico's largest clandestine graves discovered - from Al Jazeera English