MEXICO CITY - A state government in southern Mexico found itself playing middleman Thursday in negotiations involving a gang of drug traffickers who already released a kidnap victim and a band of armed, angry citizens who briefly held a crime boss' mother seeking to take back control of their lawless, opium-country town.

The Guerrero state government sent police to spirit away Maria Felix de Almonte Salgado, the mother of drug gang boss Raybel Jacobo de Almonte, known as "El Tequilero," after residents of the town of Totolapan got a kidnapped businessman back from the gang in return.

The strange standoff emerged after townspeople tired of kidnapping, extortion and killings formed an armed vigilante group and seized Mrs. de Almonte Salgado and about 20 suspected gang members on Monday, then posted videos offering them in exchange for Isauro de Paz Duque, a construction engineer abducted the previous day in an apparent extortion attempt.

Dozens of townspeople greeted a worried-looking de Paz Duque with cheers as he was released Wednesday night in the town square. They then turned de Almonte Salgado over to state police, who apparently handed the humbly dressed woman over to the gang. The exchange was recorded on a video shot by Guerrero state human rights officials.

The state government publicly denied negotiating with the gang, but it was clear there had been contact.

"The state government intervened as a mediator, not a negotiator. We didn't negotiate anything," Gov. Hector Astudillo told local media.

On Thursday night, a spokesman for a government co-ordination group, said officials were still discussing with the vigilantes about the release of the 20 or so suspected gang members taken prisoner. Roberto Alvarez Heredia, the spokesman, also said the 220 soldiers and police sent to the area after the confrontation were conducted an intensive search for the gang boss.

The state government's willingness to act as an intermediary was unusual, especially since it announced last week that hundreds of police and soldiers were searching for El Tequilero in the mountains. Astudillo also has complained bitterly about the proliferation of such armed vigilante groups and the problems they pose.

"One way to see this is as an act of realism," said Mexico City security expert Alejandro Hope. "Given the (government's) inability to control these illegal groups, the best it can do is to mediate between them."

Besides trafficking opium paste, El Tequilero's gang has kidnapped, killed and collected ransom and protection payments from residents.

The vigilante seizure of the gang leader's mother appeared to violate an unwritten rule of Mexico's drug war - that the families of top criminals are generally viewed as off-limits. A recent attack on the home of the mother of imprisoned drug lord Joaquin "El Chapo" Guzman occurred when the woman apparently wasn't home. That, and the unusual abduction of two of Guzman's sons a few months ago, have been ascribed to internal disputes in the drug cartel.

Townspeople may have been emboldened by the fact that the Tequileros gang is one of several small, relatively rag-tag gangs that dominate the mountains of Guerrero state, and not one of the top-level cartels. The leader's mother was humbly dressed in a simple skirt and blouse and wore a long braid.

The only known public appearance of "El Tequilero" - his nickname is literally "the Tequila Drinker" - is a video showing him drinking with the town's mayor-elect. De Alamonte mumbles inaudibly and has to be held up in a sitting position by one of his henchmen in that video.

Seldom have townspeople in Mexico won such a striking victory over drug gangs. The nearest example occurred in the neighbouring state of Michoacan, where armed citizen groups rose up in 2013 and chased out a drug cartel.

Vigilante action has become increasingly common in Guerrero, but increasingly problematic. The vigilante groups now fight among themselves in some sections of the state, and some have allegedly allied with guerrilla or criminal groups.

The governor is tired of it all. He said Tuesday, "This is something that has to end - that every time somebody gets the idea into their head of kidnapping somebody, they kidnap them."