On the late-September day when 43 students vanished from the Mexican city of Iguala, the mayor’s wife arrived at the party dressed in pink. A handsome woman with sharp features and black eyes, Maria de los Angeles Pineda was running to succeed her husband as mayor, and her campaign was in full swing.

She had bused in 3,000 people to the Plaza de las Tres Garantías, and pictures show a meticulously-organized stage, replete with a massive picture of Pineda and a sign that proclaimed: “Activity report.” Afterward, promised “Lady Iguala,” there would be dancing.

That dance, in which Pineda and her husband were seen sashaying, was just about the last moment anyone in the town of about 100,000 saw the couple — until this week. Days ago, they were arrested for allegedly orchestrating the abduction of 43 students and colluding with a local cartel in a case that has roiled Mexico, spurred massive protests and gained international attention.

Pineda, who campaigned on the slogan of “Closer to you,” has now gained the recognition she sought, but on very different terms. A growing number of observers, journalists and authorities now suspect that Pineda played a pivotal role in the students’ disappearance.

Routinely described as the “The First Lady of Murder,” “The First Lady of Narcotics” or the “Queen of Iguala,” Pineda was the “key operator” of Iguala’s criminal network, gang leaders told the local press. Pineda, one-half of the “Imperial Couple,” governed the Mexican city from the shadows, locals told reporters, and planned to seize control of it outright in the upcoming elections.

The story of Maria de los Angeles Pineda, who built her fortune in gold and reportedly has deep family ties to local criminal organizations, illustrates the endemic collusion between state and criminal actors in the region, where politics, business and cartels converged to take a town hostage. It has raised a series of troubling questions for Mexico, which analysts say is on the brink of “explosion” over the events in Iguala. The search for the abducted students, which has overshadowed President Enrique Pena Nieto’s agenda, has failed to turn up any of the missing. But it has unearthed a series of unrelated mass graves, filled with bodies belonging to people few knew were missing.

“Official statements that the 38 bodies found so far in 10 makeshift mass graves are not the students have exacerbated rather than calmed public anger, as now the other question is, ‘Who are these trussed up, tortured, headless or charred corpses?'” Mexican poet Homero Aridjis wrote in an impassioned essay. “Will there be an investigation to find the perpetrators? Or will time be allowed to pass until public indignation subsides, and these cases will join the roughly 98 percent of unsolved homicides in the country that have been swept under a rug as high as the Pico de Orizaba, Mexico’s tallest mountain?”

For Mexican authorities, it appears those investigations can indeed wait: They have just detained “Lady Iguala” and her husband, Mayor Jose Luis Abarca. Police found the couple squatting in an apparently abandoned, decrepit house in a lower-class section of Iztapalapa, which sits 120 miles north of Iguala in Guerrero state.

Theirs was an unusual path to prominence. Abarca grew up in a family that sold hats and wedding dresses, according to the Yucatan Times. Those mercantile endeavors ultimately gave way to something more profitable: gold and jewelry. It was around that time he met his wife, a sister of powerful local cartel brothers. One was a henchman for the since-killed cartel leader, Arturo Beltran Leyva. The other would go on to lead a cell of the prominent Guerreros Unidos, which operated around Iguala.

“The Pinedas, as they were known, controlled the drug trafficking in Guerrero, and partly in Morelos, in the name of the Sinaloa Cartel,” reported German broadcaster Deutsche Welle. “One of the Pineda brothers, Salomon, has been identified as the head of a cocaine distribution network that allegedly started in Colombia and Venezuela” and “reached the city of Atlanta, Georgia.”

Closer to home, the husband and wife got busy selling gold. They soon became wealthy from the trade, Borderland Beat reported. “Both became owners of dozens of shops in the jewelry center and of a commercial plaza, of houses and ranches,” the news blog said. They eventually came into contact with some local political bigwigs, who tapped Abarca to enter a mayoral contest he ultimately won. But once he was ensconced in that position, CNN Mexico reported it became clear who was the real force in the couple.

Described as “hard and difficult,” she was feared by many around town, CNN said. “She ruled the town,” one state leader who requested anonymity told the news network. “The mayor did everything she wanted.”

One man named Carbajal Justin Salgado complained about her to state leadership, and an unknown gunman arrived at his house in March and shot him dead, Borderland Beat said. “What we know and the information we have been given by peers who work at city hall … is that the lady made decisions, important decisions in the management of affairs in the council,” an anonymous source added.

But she wanted the title of mayor and soon announced her candidacy, enumerating what she described as her many good works on a frenetically updated Facebook profile. On Sept. 26, the day of the Plaza’s campaign event, she was greeted by an unwelcome surprise: A group of student teachers was going to make noise that would would disrupt the festivities.

“Teach them a lesson,” numerous reports quoted her as saying. According to government statements reported by the Toronto Star, her family’s cartel cooperated with the local police to confront the students — and in the ensuing violent melee, 43 young men simply vanished, leaving behind a set of clues that reveals more about the region’s political apparatus than their whereabouts.

“It is a global confession,” journalist Julio Hernandez Lopez wrote. “A collective X-ray, a clarifying revelation of the mechanisms of understanding between the economic powers, in this so-called organized crime, and the politicians, all of whom, in reality, are one and the same.”