The dismembered bodies of both employees -- Adrian de la Torre, 25 and Julieta Calvillo, 58, -- were found January 12, along with that of a third official from the prosecutor's branch office in the city of Gomez Palacio. That city and neighboring Torreon have become a primary battlefront between the Sinaloa organization and the ruthless Zetas gang, with scores of executions tallied in recent months.
Flanked by two rifle-wielding and helmeted men in camouflage uniforms and answering questions from an off-camera inquisitor, both Calvillo and De la Torre said that Sinaloa operatives posing as state officials were working inside the prosecutor's office to gain control of Durango for the cartel.
"I've talked to some of them and they say they are Mayo Zambada's people. And they are here to take the plaza," De la Torre says calmly in the video posted by Blog del Narco and Borderland Beat, referring to Sinaloa lieutenant Ismael Zambada, alias "El Mayo," and using the slang for criminal control of a city or state.
Calvillo said the Zambada gang had purchased influence with Durango Governor Jorge Herrera and "El Rosso," presumably Jose Antonio Rosso, chief of Durango's state police.
[See InSight Crime's Sinaloa Cartel profile]
"They bought the plaza," Calvillo, who identified herself as a public prosecutor, said of the Zambada operatives. "They bought it from the governor. He is the one organizing everything, together with El Rosso."
Calvillo estimated that "about 20" Sinaloa operatives had infiltrated the prosecutor's office in Gomez Palacio. She said officials send suspected gangsters to the Durango state capital where they are tortured to extract information then turned over to a local gang -- run by the Cabrera family -- that operates on Zambada's orders.
The accusations in the video echo those in banners recently strung up in Durango, all accusing the governor and Rosso of collaboration with the Sinaloa Cartel.
"If the governor and Rosso insist on delivering this plaza to the Cabreras they are going to get screwed," warned an unsigned recent banner. "This war will be long and bloody. Get a grip on yourselves because I am coming for Durango."
State officials deny collusion with gangsters, saying De La Torre and Calvillo were forced to read from a script fabricated by their abductors. The Zetas instead are seeking revenge for the governor's December closing of a prison they controlled in Gomez Palacio following a deadly riot there, Sonia-Yadira de la Garza, the state's chief prosecutor, told Insight Crime.
"We totally reject these accusations," said De la Garza, adding that De La Torre was a messenger in the state coroner's service and Calvillo was a secretary not a prosecutor. "There are no gangsters working inside the prosecutor's office. What they want is that the authorities don't do our jobs."
Insight Crime Analysis
Such videotaped confessions, usually followed by the brutal murder of those questioned, have been a mainstay in Mexico's gangster wars. The videos, as well as banners hung in public places, frequently accuse various officials of collusion with one gang or the other.
Federal officials and independent analysts have suggested that those being questioned often have been fed their statements for propaganda purposes.
Still, gangsters' support from government officials at every level has crippled the Mexican federal government's attempts to bring the violence under control. The Roman Catholic archbishop of Durango famously commented two years ago that Sinaloa kingpin Joaquin "El Chapo" Guzman was omnipresent in the state, unimpeded by authorities.
What is certain is that Gomez Palacio and neighboring Torreon, which is in Coahuila state, have become one of Mexico's bloodiest gangland battlegrounds as the Zetas battle for control against Sinaloa Cartel factions. Scores have been killed in massacres, prison riots and executions.
Mexico's new president, Enrique Peña Nieto, whose strategy to sharply reduce the drug war violence will depend upon effective law enforcement in the embattled states, faces heavy odds.
Coahuila is a Zetas stronghold, as is Zacatecas, which borders Durango to the south. Sinaloa Cartel factions hold sway in most of Durango.
[See InSight Crime's Zetas profile]
But Durango also suffered a bruising battle in 2011 between the Cabreras and another Sinaloa faction which, according to an article in Proceso magazine citing Mexican federal investigators, had fallen out of favor with El Chapo and other cartel leaders.
Police last year pulled the remains of some 350 casualties of that fight from clandestine graves in and around the state capital, also called Durango. Victorious, the Cabreras now are taking on the Zetas in Gomez Palacio and Torreon.
Like the above-mentioned banner promises, this likely is going to be long and bloody.