Editor's note: In our Behind the Scenes series, CNN correspondents share their experiences in covering news and analyze the stories behind the events. Here, CNN's Harris Whitbeck describes a recent Mexican drug raid that he accompanied.

This young boy played music that authorities said was a warning from drug lords that they were watching.

CULIACAN, Mexico (CNN) -- The boy looked to be about 12 or 13 years old. Chubby, he struggled a bit with his bicycle as he rode to where we stood. He had a slight smirk as he played a tape that blared music from speakers tied to his bike.

The tune was an ode to Edgar Guzman, the son of a local drug kingpin who was killed by a rival drug gang in a shootout May 10.

It was a message from the cartel to the cops, said Gen. Jose Antonio Guzman, the Mexican police commander heading up a raid on a house this day.

The drug lords had sent the boy to let everyone know they were watching.

It was a chilling moment in a city that has gained a reputation for being one of the most dangerous in Mexico. Watch Mexican cops raid drug safehouse »

Pitched battles between rival drug gangs, assassinations of police officers and ambushes on city streets have made life hell for many residents of Culiacan. A city of more than 600,000 people, Culiacan is on one of the nation's main highways along the west coast. Map: See where Culiacan is located »

Shortly after the young boy was paraded in front of us, dozens of armed police stormed a house, uncovering high-powered rifles and other weapons, sophisticated communications equipment and a substance believed to be a base used to make methamphetamine sold on the streets.

A man at the house fled over a rooftop before he could be detained.

It was a small victory in what authorities say is a long and bloody battle.

"I feel we are making progress," said Guzman, the federal police commander. "Let's see how long it lasts."

Guzman is leading the fight in Mexico's war against drug cartels in Culiacan, the capital of the northern Mexican state of Sinaloa that has become a key battleground about 600 miles from the U.S. border.

Authorities say an estimated 300 tons of cocaine passes through Mexico on its way from Colombia to the United States each year. The U.S. Drug Enforcement Administration says that about 90 percent of all cocaine that comes into the United States passes through Mexico. It also says Mexico has become the largest foreign provider of meth to the United States, supplying about 80 percent of the meth consumed in the States.

It's no wonder that the pitched fight for control of the lucrative drug trade has become more intense as Mexican law enforcement has tried to put the squeeze on drug lords.

"This has become a turf war between rival gangs," Guzman said. "They are trying to gain control of Sinaloa state and are arming and rearming themselves to fight their enemies."

The battle against the cartels intensified last year. Shortly after taking office in January 2007, President Felipe Calderon vowed to take more aggressive action against drug traffickers. He sent thousands of military and federal police to fight them in the states where the cartels waged the most influence, mostly in central and northern Mexico.

Federal troops were sent in because, government sources say, local and state police in many regions in northern Mexico tip off drug gangs to raids, provide protection to them and fail to arrest gang members.

How many local police might be tied to the cartels?

"A significant amount that is unacceptable to many, including the Mexican government," one U.S. anti-narcotics official said on condition of anonymity.

The government's crackdown has met a vicious response: Authorities say more than 1,000 people -- including gang members, police and civilians -- have been killed in drug-related violence in Mexico since the start of this year, primarily in the northern and central parts of the country.

Several high-level and mid-level federal police officers have been shot and killed, and the killings have begun to strike closer to home. One of the most shocking took place May 8, when Mexico's highest-ranking federal police officer, Edgar Millan, was gunned down outside his home.

At least 170 local police officers have been killed, some who were doing their jobs and others who were involved with drug gangs and killed by rivals, authorities say. Other police have resigned out of fear for their lives.

Some analysts say the violence is a reaction by drug lords feeling the heat from the federal government. Others say that as the drug cartels are squeezed by the government, they've begun fighting rival cartels to preserve and control their turf.

The U.S. counter-narcotics official said the violence won't end any time soon.

"This will be a muddy, bloody uphill climb," he said, adding that Calderon "knew the cancer had to be cut out before it cut him down." The United States is supplying the Mexican government with millions of dollars in support and high-tech equipment.

The general in charge of federal police in Culiacan says time will tell whether all the efforts have been successful.

"If we can keep the violence down for the next three months, I'll feel satisfied," Guzman said.

But some analysts feel the government's head-on approach is misguided. They say military or police action will not be enough to curb the cartels in Mexico.

Samuel Gonzalez, a former high-level anti-organized crime official, says authorities need to go after the cartels' financial networks.

"If you fight them as the government is doing right now but don't take all their businesses down, they will just use all their money to bring more violence against the government," said Gonzalez, who now works as a security analyst in Mexico.

On the ground, the foot soldiers fighting on behalf of the government are a bit more optimistic.

Raids like the one on the safe house that netted weapons and a small amount of meth base happen at least two to three times a week. They might look small, police say, but they are still victories.

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