Marvin Gonzalez waves to shopkeepers as he enjoys a morning walk through the sunny, working-class resort of Ilopango. His cellphone rings nonstop with residents seeking his support for anything from dealing with a drunk who won't pay his bar bill to reporting an attempted rape.

Gonzalez is not a police chief, nor a politician. The 31-year-old plug of a man is the local leader of the Mara Salvatrucha, a gang formed by Central American immigrants in California and now designated by the U.S. as a transnational criminal organization.

But in Ilopango and communities across El Salvador, the Mara Salvatrucha and their arch rivals, the 18th Street Gang, are de facto rulers. A truce declared two years ago briefly tapered their bloody gang war, but the cease-fire had an unintended consequence: It gave the gangs breathing room to grow even stronger. Now, violence is on the rise again.

The murder rate has climbed since the truce unraveled in late 2013. Last month, the average was up to 10 a day compared to six during the truce.

This wasn't what was expected when gang leaders reached a truce in March 2012. Observers hailed the agreement as the start of a new era of peace for El Salvador, a model to be followed by other countries, and one that had taken cues from the peace process that, two decades earlier, ended El Salvador's 12-year civil war.

"They stopped the civil war with dialogue, so why shouldn't we talk?" said Gonzalez, speaking with a quiet sophistication. "Nobody is going to cease to belong to the gang. But this way, we can begin to rebuild the social fabric."

Former adversaries in El Salvador's civil war joined together to help broker the peace between the gangs. In 2011, then-Security Minister Gen. David Munguia asked Raul Mijango, a former guerrilla fighter who'd served in congress, to go into prisons to talk to gang leaders and negotiate an end to the bloodshed. Violence had reached a peak that year of nearly 70 killings per 100,000 people, one of the highest homicide rates in the world.

After the truce was reached, an order went out to stop the killings, and by mid-March 2012, the government proclaimed that the homicide rate dropped from 14 a day to six.

The government said it facilitated talks but promised the gangs nothing. Nevertheless, imprisoned leaders were given better quarters and expanded privileges. Prosecutors are investigating possible arms trafficking related to the truce. Last month, a Spanish priest who supported the truce was arrested for allegedly delivering contraband to the prisoners, including cellphones with internet connections.

Gonzalez had been in prison for killing a rival gang member when the truce was signed. He gained his freedom months later, determined, he said, to keep his children from following his criminal path.

"That's not the future we seek," he said, speaking to a reporter on an August day while having lunch by Ilopango's lakeshore, which is spotted with ramshackle restaurants serving tilapia caught by local fishermen.

Lying east of San Salvador, scenic Ilopango has special status among the gangs. Last year, the two bands agreed to make it one of the country's first "violence-free zones." Gonzalez, in backward baseball cap and shirt tails, appeared publicly alongside Gen. Munguia to announce the accord for the suburb, a popular weekend getaway spot for the capital's residents.

But free of violence does not mean free of gangs. The entrance to Ilopango is still controlled by the Mara Salvatrucha, while a northern stretch of the suburb is controlled by 18th Street. Nothing about the agreement has impeded Gonzalez or any of his gang from walking around freely and exerting full control. In fact, it's only strengthened their power.

Mass graves still are dug up in Ilopango, filled with young people who were killed even during the truce. Restaurants and other businesses pay extortions. Residents who cross enemy gang territory risk getting killed. Weekend beachgoers are watched by clusters of teenage lookouts on street corners, their guns stored nearby.

Gonzalez insists the truce is paying off. He touts new programs, such as one that employs 40 of Ilopango's 700 active gang members on a chicken farm, and a greenhouse project funded by the European Union. Soon, he said, he'll declare the town extortion-free and has already begun with businesses catering to tourists.

"Last Christmas," he said, "the owners of the lakefront restaurants made lunch for 200 (gang members) to thank them for stopping the extortions."

Under Gonzalez's watchful eye, one restaurant owner told the AP that, indeed, he had never been extorted.

People in other parts of greater San Salvador spoke more freely, but without giving their names.

"When you don't pay, the gangs kill you. And if you leave an empty space, they take it over for their activities," said one police officer in Mejicanos, another suburb, who would only give his badge number. "In almost every neighborhood, you encounter the same thing."

The officer said at one apartment building under his watch, gang threats led 14 families to flee their homes rather than make extortion payments.

Spreading fear and ruling with near impunity, the gangs are one of the top reasons behind the record exodus of unaccompanied minors who have overwhelmed U.S. Border Patrol agents since last October. A recent United Nations report estimated about 61 percent of children who reached the U.S. border last year were fleeing problems caused by gangs.

Nearly 80 percent of small businesses, which make up 90 percent of El Salvador's economy, are victims of extortion, according to Ernesto Vilanova, president of the National Council of Small Business. Some 84 percent of victims never report it, he said.

"If they wouldn't do it before, the citizens sure aren't going to report the gangs that extort them now that they've seen them side-by-side with the political authorities," said Rodrigo Avila, former head of the National Police and an opposition presidential candidate in 2009. "They're an authority parallel to the state in many towns."

For many, the truce was a good idea that turned bad. Mauricio Arriaza, San Salvador's municipal police chief, said he doubts that even the highly touted reduction in violence was real.

"We're sure, without a doubt, that the gangs continued assassinating and burying their victims in unmarked graves," he said.

Israel Ticas, a forensic investigator who excavates mass graves, said the true results of the truce are still being uncovered.

"Only in five or 10 years will we know what really happened," Ticas said. "When we've found all the graves."