The suspect cruised around in an SUV that had been reported stolen. He toted corrido music glorifying drug smugglers and hit men, and allegedly helped them operate in this beach resort.

And until a few weeks ago, he was Cancun’s police chief.

Now Francisco Velasco is in custody in Mexico City while federal authorities investigate whether he took part in the killing last month of a retired army general who had been hired to revamp the city’s police force.

The 57-year-old Velasco, who was in his fourth stint as Cancun’s police chief, has not been charged. But federal officials say they believe he protected seven people accused of kidnapping and killing Gen. Mauro Enrique Tello and two others.

The trio disappeared in downtown Cancun late on Feb. 2. Their bodies, riddled with bullets, were found the next morning beside a highway, 15 miles away. The general’s arms and legs had been broken, apparently as a result of torture. Authorities believe the slaying was the work of the Zetas, much-feared enforcers for drug-smuggling gangs.

The murky case has hit Cancun like one of the tropical storms that lumber in off the Caribbean, setting off charges that a police force touted as one of the most trustworthy in the nation is rife with corruption.

A high-profile killing in the country’s signature beach resort is the last thing Mexico needs at a time when drug-related violence has scared away visitors from areas such as Baja California. More than 6,000 people were slain last year, predominantly in areas near the U.S. border, while President Felipe Calderon has struggled to root out corruption in law enforcement at every level.

“The reality is that Cancun, like the rest of Mexico, is at war,” said Cesar Muñoz, an editor at Novedades, a daily newspaper in Cancun that has closely followed the Tello case. “It’s at war with the drug cartels.”

The slayings are raising uncomfortable questions about how deeply corruption has infected the city’s government. The director of the Cancun jail and head of the city’s traffic division also have been detained, according to news reports. There is no sign, however, that Mayor Gregorio Sanchez, a self-styled reformer elected last year, is under investigation.

“There is corruption,” Cancun’s new police chief, Maria Esther Estiubarte, the first woman to hold the post, conceded in an interview a few days after taking the job. But she said it was limited. “It doesn’t put the tourist destination at risk,” Estiubarte said.

The incident does not seem to have spooked spring break vacationers, who already are pouring into the palm-lined beach region. The killings took place miles from the sprawling resorts and high-rises, where security is strict and crime against tourists is rare.

The surrounding state of Quintana Roo remains relatively tranquil compared with other states where drug violence has exploded. The state registered about 20 homicides last year.

But although roadside billboards welcome visitors to “paradise,” Cancun has long had an unsavory side that looks nothing like the brochure pictures of sugary beaches and deep-blue waters.

The area is a well-established transshipment point for cocaine smuggled by air from South America or overland through Central America on its way to the U.S. A former Quintana Roo governor, Mario Villanueva Madrid, awaits extradition to the United States on charges that he took payoffs in exchange for helping Mexican traffickers move tons of cocaine through his state.

In August, a pile of 11 decapitated bodies turned up in the neighboring state of Yucatan, in what was believed to be an organized-crime hit. A 12th headless body was found the same day in a separate spot. The killings were attributed to the Zetas.

Many residents worry that the killings augur a menacing new phase for Cancun. Apart from the main tourist zone, drug sales flourish on the streets of the shabbiest barrios, where prostitutes beckon from the shadows and fear of gang members keeps residents from venturing out more than a few blocks at night.

A stream of job seekers from Mexico’s impoverished south means business for flophouses that charge as little as $50 a month, but it has strained the city’s resources. Along rutted streets on the edge of town, squatter families inhabit stick shacks that are lighted by electricity stolen from nearby utility lines.

The fast growth has turned this other Cancun into a traffic-clogged city of about 750,000 -- big enough, some say, to serve as cover for the drug syndicates that operate elsewhere in Mexico.

“This is the moment. Cancun has grown a lot and now looks like a good cave, a good hiding place, for these activities,” said Father Rafael Ruiz, a parish priest in a graffiti-spattered part of what he calls the “Mexican Cancun.”

Around town, mystery cloaks the case of the slain general. Tello’s body, along with those of army Lt. Getulio Cesar Roman Zuñiga and Juan Ramirez Sanchez, who was the mayor’s nephew, were found in a pickup next to the road to colonial Merida, which sits across the Yucatan peninsula about 175 miles from Cancun.

They were seized apparently in downtown Cancun hours after Mayor Sanchez introduced Tello to other municipal staffers as his new security advisor, with the task of creating a separate elite police squad.

Former top infantry commander of the Mexican army, Tello had completed a command tour in the western state of Michoacan as part of Calderon’s military-led offensive against drug traffickers. He had arrived in Cancun in late January.

Sanchez had asked Tello, known as a well-trained and tough commander, to organize a SWAT-type team of 100 former soldiers that would answer only to the mayor; essentially a parallel force above the reach of then-Police Chief Velasco.

The mayor said he wanted a new force that would remain “outside the contamination” of the 2,000-officer police department.

“We don’t want to put all our eggs in the same basket,” he said in an interview.

Sanchez said he did not suspect Velasco of wrongdoing, but believed that there were dirty cops on the force, despite months of culling.

A popular businessman who ran as candidate of a leftist coalition, Sanchez has cultivated the image of a reformer in less than a year in office. He announced a “zero tolerance” policy on corruption and has fired 150 suspect cops. In December, Sanchez said, the federal government named Cancun’s force the third-most trustworthy in the country.

Skeptics point out that it was Sanchez who hired Velasco, a balding, old-school cop with a push-broom mustache and the nickname “Viking.” The mayor also continued to back his pick after investigators in the Tello case began to focus on the chief. If Velasco was up to no good, residents ask privately, how is it possible the mayor didn’t know?

On Feb. 11, a week after the killing, federal authorities said they had arrested seven members of an alleged Zetas cell in Cancun. They included a former soldier and an active-duty Cancun police officer.

Federal prosecutors said they had received testimony that Velasco offered “protection and aid” to the cell and had been seen meeting with its leaders. Velasco is under a 40-day detention during the investigation.

After Velasco was hauled off to Mexico City for questioning, Quintana Roo prosecutors said a vehicle check on his Nissan Armada, painted with police logos, indicated that it had been reported stolen in Mexico City in 2006. Inside were CDs with narcocorridos about the Zetas. Songs included “Z Dynasty,” “Pact of Honor” and “Eagles Go Alone.”

The motive for the killing is unclear. One theory is that Tello was set up by drug traffickers he battled in Michoacan. Another holds that the Zetas saw him as a threat to operations in Cancun.

Mayor Sanchez said he was committed to creating his SWAT force once he found someone to run it. But the general’s killing has left many in Cancun uneasy about the dark forces working in their midst.

“There is a lot of fear,” said Ruiz, the parish priest. “We know that these people, who have little sense of morality or justice, are among the people.”

ken.ellingwood@latimes.com