MORELIA, Mexico -- On a cool September evening, about a half hour after the sun set on the rose-colored Baroque cathedral of this colonial city in western Mexico, three men burst into a Coca-Cola distribution center on the edge of town.

The robbers pistol-whipped three security guards, grabbed thousands of pesos in cash and fled into a poor neighborhood of crumbling brick houses. Sirens screaming, state police arrived to find the white Nissan Sentra they believe was the getaway car being engulfed in flames.

"You can't even go out at night here," homemaker Yolanda Villa said, poking her head out the door of her home around the corner. "They beat you, kidnap you, rob you," her 9-year-old son Luis said, finishing her sentence.

In cities and towns across Mexico, a nearly six-year offensive against drug cartels has been accompanied by a surge in common crime: assaults and robberies that grab no headlines but make life miserable for ordinary citizens.

Some experts blame the drug war for distracting law-enforcement from pursuing common criminals. Others say drug cartels have turned to common crime as a way to fund their clashes with each other, and with troops and federal police.

Some of the first effects were felt in Morelia, the once-sleepy capital of Michoacan state, where Mexico launched its war on drugs.

The clashes in Michoacan began when local traffickers who had worked with the Gulf cartel became disenchanted with the tactics of that cartel's brutal enforcement wing, the Zetas, and formed their own gang with the avowed intention of keeping the Zetas out. The state's Pacific coastline and rugged, green countryside are ideal for clandestine operations such as methamphetamine labs.

A war erupted between the new group, which called itself La Familia Michoacana, and the Zetas, military defectors known for exploiting areas they control through extortion, kidnapping, drug trafficking and other crimes.

Less than two weeks after taking office in December 2006, President Felipe Calderon ordered thousands of troops to Michoacan, his home state, with orders to quash the violence.

Hundreds were killed across the state in battles between traffickers and in government actions. In September 2006, gunmen threw five severed heads onto the dance floor of a bar in the city of Uruapan, a crime so ghastly it made international news.

Meanwhile, common crime began to increase, with reported robberies rising 35 percent between 2006 and 2011 in the jurisdiction that includes Morelia, an international tourist attraction once best known for its Spanish-language schools, lush green parks and immaculately preserved 16th-century architecture. Robberies appear to be on track to rise again this year.

Nearly six years later, the military remains in Michoacan. Its operations have helped splinter La Familia into two dueling groups that themselves are fighting with at least two other cartels, including the Zetas, along the edges of Michoacan.

Soldiers and federal officers still clash almost daily with heavily armed cartel gunmen. Kidnappings are frequent, and discoveries of dismembered, beheaded bodies are a regular occurrence throughout much of the state. Homicides rose 68 percent in the state between 2006 and 2011. They rose 35 percent nationwide.

As for the street crime, state officials say they are making progress in Morelia through purges of corrupt and incompetent police officers and better management of the remaining police, and they say some crimes, including several types of robbery and assault, are decreasing. But Morelia residents say they don't feel safer.

Joe Maria Cazares Solorzano, president of the Morelia-based state commission on human rights, said people in the region have learned to expect the unexpected.

"Ten, 12 years ago, you never heard a siren, and never heard a helicopter. The police never flew over the city," Solorzano said. "Now it's a cause of constant anxiety, hearing ambulances, sirens, police and army helicopters flying over the city. So much has changed in terms of security, and it's very sad."

A similar wave of common crime has hit other Mexican cities.

Nationwide, robberies increased 45 percent between 2005 and the start of 2012, with the number of bank robberies almost quadrupling, from 200 to 768.

Mexicali, on the California border, saw a 70 percent surge in robberies between 2006 and 2011, although the figures seem to be falling slightly this year. The Pacific coast resort city of Acapulco, hit by a vicious struggle among small local drug gangs, saw robberies rise by around 400 percent. The northern city of Chihuahua saw a nearly 30 percent rise.

For decades, drug cartels controlled swaths of territory largely uncontested, letting them focus on moving massive amounts of narcotics north through Mexico, striking deals with corrupt officials with the least possible disruption to both sides. With the government's assault on the cartels, many have splintered, lost control of territory and gone to war against each other and against authorities.

Edgardo Buscaglia, a senior scholar at Columbia University who studies organized crime in Latin America, said the cartels have turned to other illegal businesses to make money.

"They need franchises, youth gangs working for them," said Buscaglia. "You have an unemployed army of youth and franchises that are serving all these organized crime groups. That creates a huge tsunami of ordinary crime."

On March 5, 10 blocks from the manicured lawns of Morelia's idyllic central square, two armed men held up a Bancomer bank branch, shooting a woman in the shoulder and getting away with 123,000 pesos in cash, about $13,600. Over the next seven months, Morelia was hit by an average of one bank robbery a month, including two on a single day in August. In 2006, Morelia had just five bank robberies all year.

"The authorities are focused on something else, therefore the likelihood of anyone being detained goes down," said Alejandro Hope, a former high-ranking official in Mexico's domestic intelligence agency. "This is the type of crime that affects the man on the street. Most of the fears and concerns of common people have to do with this."

Inspector Osvaldo Torres, a state police official whose jurisdiction includes Morelia, said he believes most street crime has no connection to the drug cartels.

"It's more ordinary people who do this kind of thing," he said. "In fact, here organized crime doesn't get involved in this sort of thing."

Torres said he has seen a drop in street crime over the last eight months, partly because officers are responding more quickly to crime now that their work shifts has been reduced from 24 to 12 hours and they are less tired on the job.

Federal statistics show the overall number of robberies outpaced population growth, rising more than 6 percent in the first eight months of this year, to 5,915 for a city with a population of more than 730,000 people.

Carlos Arrieta, a spokesman for state prosecutors, said he could not speak in detail about the causes of crimes that occurred before the current administration took office. But he attributed much of the rise to the increasing population of Morelia, which has expanded by roughly 100,000 people over the last decade.

"Morelia has grown exponentially," said Arrieta. "It's like when you plant a lot of trees in an orchard, you're going to have more avocados, rotten and ripe ones. It's exactly the same."

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  • Oct 9, 2012

    Marines say they have killed the leader of the brutal Zetas drug gang, Heriberto Lazcano, alias "The Executioner," in a shootout. <em>Caption: This photo released by Mexico's Navy on Tuesday, Oct. 9, 2012 allegedly shows the body of Zeta drug cartel leader and founder Heriberto Lazcano while in the possession of Mexico's Medical Forensic Service (SEMEFO) in Sabinas, Mexico. (AP Photo/Mexico Navy)</em>

  • Oct 4, 2012

    The son of the former chairman of Mexico's Institutional Revolutionary Party is found dead. <em>Caption: In this Oct. 15, 2007, photo, Jose Eduardo Moreira Rodriguez poses for photographers in Saltillo, Mexico. (AP Photo/Alberto Puente)</em>

  • Sept 4, 2012

    Mexico captures a leader of the country's Gulf Cartel, Mario Cardenas, alias "Fatso." <em>Caption: Mexican Navy officers flank Mario Cardenas Guillen, also known as "El Gordo" and "M-1," during his presentation to the media in Mexico City, Tuesday, Sept. 4, 2012. (AP Photo/Alexandre Meneghini)</em>

  • Aug 24, 2012

    Mexican police shoot and wound two U.S. Embassy employees, whom sources later identify as CIA operatives, just south of Mexico City. <em>Caption: In this Aug. 24, 2012, file photo, an armored U.S. embassy vehicle is checked by military personal after it was attacked by unknown assailants on the highway leading to the city of Cuernavaca, near Tres Marias, Mexico. (AP Photo/Alexandre Meneghini, File)</em>

  • August 14, 2012

    Armed men storm a bar in Monterrey, killing eight men in a hail of bullets, in an apparent dispute over drug dealing. <em>Caption: Police forensic investigation vehicles sit parked outside Matehuala Men's Club after a shooting inside the night club in Monterrey, Mexico, early Tuesday Aug. 14, 2012. (AP Photo)</em>

  • May 13, 2012

    Suspected drug gang hitmen dumped 49 mutilated bodies, stuffed in bags, on a highway outside the northern industrial city of Monterrey. <em>Caption: Federal police stand guard on a vehicle behind a forensic truck containing bodies found on the highway connecting the northern Mexican metropolis of Monterrey to the U.S. border, along the Reynosa-Cadereyta road, in the town of San Juan near the city of Monterrey, Mexico, Sunday, May 13, 2012. (AP Photo/Christian Palma)</em>

  • May 4, 2012

    The bodies of nine people were found hanging from a bridge and 14 others found dismembered in the city of Nuevo Laredo, just across the U.S. border from Laredo, in Texas. <em>Caption: Four of nine corpses are seen hanging from a bridge in the Mexican border city of Nuevo Laredo, Tamaulipas state, early morning on May 4, 2012. (RAUL LLAMAS/AFP/GettyImages)</em>

  • Feb 19, 2012

    A fight between rival gangs at a prison just outside Monterrey in northern Mexico leaves 44 dead. <em>Caption: Araceli Guevara Ontiveros, the sister of Francisco Guevara Ontiveros --one of the 44 dead in a riot at The Apodaca prison-- is comforted while crying on his coffin during his wake in Monterrey, Nuevo Leon state, on February 21, 2012. (Julio Cesar Aguilar/AFP/Getty Images)</em>

  • Nov 24, 2011

    More than 20 bodies are found in cars in Mexico's second city, Guadalajara, a day after the burned bodies of 16 people are found in the home state of the country's powerful drug lord, Joaquin "Shorty" Guzman. <em>Caption: A member of the forensic service carries one of the 26 corpses found this morning in three vehicles abandoned in Mexico's second most populous city of Guadalajara, Mexico, on November 24, 2011. (HECTOR GUERRERO/AFP/Getty Images)</em>

  • Oct 6, 2011

    Mexican security forces find 32 bodies at several locations around Veracruz, just two days after the government unveiled a plan to bolster security in Veracruz state. <em>Caption: Mexican army soldiers walk towards their vehicle after seven bodies were found inside a vehicle in the Gulf port city of Veracruz, Mexico, late Friday Oct. 7, 2011. (AP Photo/Felix Marquez)</em>

  • Sept 20, 2011

    Thirty-five bodies are found abandoned in two trucks on an underpass in the eastern Gulf city of Veracruz, which had been largely untouched by the violence. <em>Caption: Mexican marines stand guard in streets of Veracruz State, Mexico on 24 January 2012. (JOHAN ORDONEZ/AFP/Getty Images)</em>

  • Aug 25, 2011

    Masked gunmen torch a casino in Monterrey, killing 52 people, most of them women. The attack takes less than three minutes. <em>Caption: Relatives of victims cry in front of the Casino Royale, in Monterrey, Mexico, on August 27, 2011. (Ronaldo Schemidt/AFP/Getty Images)</em>

  • Aug 20, 2011

    Five headless bodies were found in Acapulco, taking the number of people killed in the popular Pacific resort to at least 25 in that one week. <em>Caption: Forensic personnel move the corpse of a person murdered in a hotel at the La Guinea neighbordhood in the town of Acapulco, Guerrero state, Mexico on August 24, 2011. (Pedro PARDO/AFP/Getty Images)</em>

  • April 2011

    Officials unearthed the first of what turned out to be more than 450 bodies buried in mass graves in the northern states of Durango and Tamaulipas. <em>Caption: Forensic personnel unload at the morgue bodies of people killed execution-style in Matamoros, Tamaulipas State, Mexico, on April, 11, 2011. (STR/AFP/Getty Images)</em>

  • Aug 25, 2010

    Marines found the bodies of 58 men and 14 women at a ranch near the Gulf of Mexico in Tamaulipas state, 90 miles from the Texas border, after a firefight with drug hitmen in which three gunmen and a marine died. <em>Caption: A worker wearing protective suit and boots walks between two refrigerated trucks parked outside a funeral home where the bodies of 72 men and women that were allegedly killed by the Zetas drug gang, are kept in San Fernando, just 100 miles from the the Mexican border with the U.S. near the city of Matamoros, Thursday Aug. 26, 2010. (AP Photo/Guillermo Arias)</em>

  • July 24, 2010

    Police unearthed 51 bodies in a grave outside Mexico's business capital, Monterrey, in northern Mexico over several days. Some corpses were burned beyond recognition. <em>Caption: View of the remains of two burnt bodies found in Monterrey, Nuevo Leon state, on October 20, 2010. The bodies were found under burnt wooden pallets. (Dario Leon/AFP/Getty Images)</em>

  • July 18, 2010

    Gunmen burst into a birthday party in the northern city of Torreon, using automatic weapons to kill 17 party-goers and wound 18 others. Mexican authorities said later those responsible were incarcerated cartel hitmen let out of jail by corrupt officials. The killers allegedly borrowed weapons and vehicles from prison guards and later returned to their cells. <em>Caption: Police officers patrol a street in Torreon, in the Mexican northern state of Coahuila, Monday, July 19, 2010. (AP Photo/Ramon Sotomayor)</em>

  • June 28, 2010

    Suspected cartel gunmen shot and killed a popular gubernatorial candidate in the northern state of Tamaulipas in the worst cartel attack on a politician to date. Rodolfo Torre, 46, and four aides from the opposition Institutional Revolutionary Party, or PRI, were ambushed on their way to a campaign event for the July 4 state election. <em>Caption: A billboard with the portrait of the candidate for Governor of Tamaulipas state for the Institutional Revolutionary Party (PRI), Rodolfo Torre, and reading 'A leader forever' is seen during his funeral at the Polyforum in Ciudad Victoria, Tamaulipas state, Mexico, on June 29, 2010. (LUIS ACOSTA/AFP/Getty Images)</em>

  • March 13, 2010

    Hitmen killed three people linked to the U.S. Consulate in Ciudad Juarez in March, provoking "outrage" from U.S. President Barack Obama. <em>Caption:The U.S. national flag flutters at half-mast at the entrance of the consulate of the United States in Ciudad Juarez, Chihuahua state, Mexico on March 15, 2010. (Jesus Alcazar/AFP/Getty Images)</em>

  • Jan 31, 2010

    Suspected cartel assailants killed 13 high school students and two adults at a party in Ciudad Juarez across from El Paso, Texas. <em>Caption: Students enter a high school in Ciudad Juarez, a city ridden by homicidal violence along Mexico's border with Texas. (Tim Johnson/MCT via Getty Images)</em>

  • Sept 15, 2008

    Suspected members of the Zetas drug gang tossed grenades into a crowd celebrating Mexico's independence day in the western city of Morelia, killing eight people and wounding more than 100. <em>Caption: From left to right: Julio Cesar Mondragon Mendoza, Juan Carlos Castro Galeana, and Alfredo Rosas Elicea, are members of a group of hitmen called the 'Zetas' shown to the press at the General Attorney's office in Mexico City, on September 26, 2008. The three gangsters confessed that they are the authors of a grenade attack that killed eight people during the celebration of Independence Day in Morelia, western Mexico. (STR/AFP/Getty Images)</em>