This story was first published Jan. 9, 2011. It was updated on June 27, 2011.
In the past four and a half years, nearly 40,000 people have been killed in Mexico's battle against powerful drug cartels. The violence and corruption is now appearing in places that would have been unthinkable just a few years ago: places like Santiago, a quaint tourist town just a few hours from the U.S. border.
Last August, Santiago's mayor, Edelmiro Cavazos, was kidnapped and killed. To understand what's happening in Mexico, you need to understand what happened in Santiago. As we first told you in January, there and elsewhere around the country, drug cartels armed with guns and cash are forcing a choice on politicians and law enforcement. That choice - as beleaguered Mexicans put it - is between silver or lead: take a bribe or a bullet.
Veronica Cavazos and her husband, Edelmiro, were enjoying a good life, raising three children. He was a successful lawyer with a family run real estate business. Then, in November 2009, at the age of 38, Cavazos was elected mayor of Santiago, a picturesque town where he and his wife grew up.
Asked if she thinks her husband was born to be mayor, Cavazos told "60 Minutes" correspondent Byron Pitts, "Probably. He had this special light, this special feeling of helping people since he was a kid."
But she was worried. "It was a dangerous time to be the mayor, in my opinion," Cavazos told Pitts.
"He was well known. You all were comfortable financially, so why do this?" Pitts asked.
"And you know what his answer was? There is something I can do to help my town, to help my people. And that's the way I'll do it," she replied.
Cavazos was eager and everywhere. He could be found with a smile at civic presentations and at every improvement project.
Cavazos told Pitts her husband had no apprehension about the job. "He was a dreamer, I think."
"A dreamer, your husband? What did he dream for Santiago?" Pitts asked.
"A perfect place for his kids," she replied.
Santiago dates back to the 1600s. Its history and natural setting make it a popular tourist destination. But beneath the postcard appearance is another Santiago, a place important to drug traffickers.
The town straddles a major highway from the drug producing regions of southern Mexico and South America. Controlling Santiago makes it easier to move shipments north to Monterrey. From there, the marijuana, cocaine, heroin and methamphetamines are shipped to cities on the border - three hours away - and smuggled into the United States.
"So from that place, you can go anywhere in the border," Ramon Garza, who has been an investigative journalist in Mexico for 35 years, explained.
"So in many ways, the drug world intersects at Santiago?" Pitts asked.
"Exactly," Garza said.
Garza says Santiago became a safe haven for wealthy drug cartel bosses who blended in with the town's other wealthy residents. "It's a place where you can hide your activities because it's a place for tourism, for nice homes, for weekends," he explained.
And for years, the drug trafficking organization in control of the region - including Monterrey and Santiago - was the Gulf Cartel. Their enforcers: the Zetas, a ruthless gang that started with former Army officers from Mexico's elite special forces.
"Hired guns," Pitts remarked. "Well-trained hired guns."
"Well-trained. They were like a SWAT," Garza agreed.
According to Garza, they were originally trained to go after the cartels, but now are part of it. "They became the Army for the cartels," he said.
Produced by David Schneider and Joyce Gesundheit