Four decapitated bodies dangle from a bridge like butchered meat, the grotesque insignia of a city torn apart by drug gangs. Passing by in a convoy of SUVs, Alejandro Gillick, a shadowy operator in America’s drug war, does not flinch.

“Welcome to Juárez,” he says.

Lawless and sickeningly violent, the Juárez depicted in “Sicario,” the borderland action movie that was released in the United States at the beginning of October, is a parched, Mexican hellhole.

But it is yesterday’s hellhole, officials and residents here say — a starkly different place from the much calmer and safer Juárez of today.

For the past couple of years, Juárez has been successfully cleaning up its act, residents say.

The city is beautifying the small colonial center, and painters are freshening up battered houses with coats of violet and lime green. Diggers are plowing empty lots in preparation for construction crews, and the city’s hundreds of factories are crying out for workers.

Bars and clubs are buzzing, and expensive cars — once hidden in garages — purr at traffic lights. Gone, for the most part, are the days of drug-fueled crime when people sped home at dusk, businesses were gutted by arson attacks and corpses were a daily spectacle.

Which is why some residents here feel so aggrieved at the portrayal of the city in the movie.

Enrique Serrano Escobar, the city’s mayor, has urged citizens to boycott the movie, and at one point threatened to sue its producers for defamation. The mayor, who has yet to see the film, which is due for release in Mexico in December, even took out ads in some American newspapers, including The New York Times, to express his objections.

“There is a whole community making an effort to restore the image of the city, and now they come along and speak ill of us,” he said in an interview.

The movie stars Emily Blunt as a naive FBI agent who gets involved in a murky operation involving a constellation of U.S. law enforcement officers and Gillick, played by Benicio del Toro. In “Sicario,” Juárez, a city of about 1.5 million, is a tense, dusty sprawl of graffiti and prowling drug traffickers.

But the movie was “out of date,” said Serrano, and it came “just as we in the city are turning in a different direction.”

Why crime in Juárez dropped so quickly is still debated: Officials and experts point to a purge of corrupt police officers and judiciary, better police training, stiffer prison sentences — including the introduction of life sentences for kidnapping, murder and extortion — and energetic efforts by community groups. Some experts, though, believe the shift had as much to do with a settlement between the warring Sinaloa and Juárez cartels.

And even as the bloodshed abated in Juárez, it surged elsewhere: The country is still reeling from the disappearance last year of 43 students in a rural town in Guerrero state, and gang violence made the Pacific resort of Acapulco the country’s most deadly city last year.

In an email, Denis Villeneuve, the movie’s director, said the film was conceived in 2010 at the height of Juárez’s troubles.

“We didn’t have the intention to harm the citizens of Juárez with our movie,” Villeneuve said. “The people who are fighting for peace deserve our respect.”

But Serrano’s outrage has resonated with residents, entrepreneurs, pastors and community organizers, who are anxious to undo the city’s ugly reputation.

A few dozen protesters gathered on the bridge between Juárez and El Paso, Texas, on Oct. 2, waving placards that declared their love for Juárez and demanding respect.

Members of a Juárez community Facebook group that organizes community projects debated whether to see the movie — which some had seen in El Paso — and whether it accurately depicted the city’s dark years.

“Look, the movie is tough, but it’s real,” said Salvador Cisneros, a painter and decorator from Juárez who saw the movie last week during a trip to Atlanta. “In fact, the reality was much worse.”

The turnaround for Juárez began in 2012 and has been dramatic. Kidnappings have plummeted — officially there have been none in 20 months — and the murder rate has fallen from as many as eight a day during the worst times in 2010 to between 20 and 30 per month now.

Businesses and day-trippers have taken note. Hotels in Juárez have occupancy rates close to 70 percent, up from a low of between 20 and 40 percent during the worst violence.

Serrano, the mayor, has teamed with the mayor’s office in El Paso, traveling on joint delegations to cities like Detroit and Chicago to promote investment.

But changing a city’s image is a slow process, and business owners and officials worry that “Sicario” could stunt the city’s economic prospects.

“If you saw that film in the United States or Europe and you were thinking of coming here, you probably wouldn’t come,” Serrano said. “If you were thinking of investing, you probably wouldn’t invest.”

Some residents also said they resented the fact the movie was not made in Juárez.

The action crosses between Mexico and the United States, but, because of security worries, the producers shot the movie in Albuquerque, New Mexico; El Paso; and Mexico City.

“At least they would have created a windfall for the city,” said Liliana Pérez, an MBA student who started the Juárez Facebook campaign a few months ago.

Roberto Herrera, one of the partners in a food court here, where diners last week munched tacos and crepes and watched a “Star Wars” movie on an overhead screen, said it drew many customers from El Paso on weekends and had been so popular that he and his partners were opening another one this month. He fears the movie could put off visitors.

“Our fear is that the movie could put people off,” he said. “It’s annoying.”

However, Samuel Schmidt, director of El Colegio de Chihuahua, a research organization based in Juárez, said the critics of the movie were overstating the effect it would have.

“Juárez’s image isn’t important to growth,” he said by telephone. “On the one hand, you have a powerful narrative about Juárez, and people are very sensitive about it,” he added. “On the other, you have a growing U.S. economy, and that means we have growth.”

Sergio, who opened a wedding business in 2008, said the mayor’s office should ease business regulations and promote the city effectively, rather than fussing about a movie. Case in point, he said: He was fined $250 last year for putting construction rubble in his own front yard and received another fine because a banner on his building exceeded size regulations.

“The role of the government is to bring investment,” said Sergio, who asked that his full name not be used because he has been the target of extortion. “It’s just a movie.”

Plus, he said, “Let’s not try to block out the sun with one finger. This city is still problematic.”

Old problems surfaced on Oct. 3 when a police commander, Jesús Eduardo Alemán Medina, was gunned down outside his suburban residence. The city was shaken by the murder, that same week, of six women. Though the women died in unconnected circumstances, the cluster of killings raised the specter of the murder of hundreds of young women that gripped the city in the 1990s.

For many in Juárez, the bad old days are never far behind. Residents became grim or tearful when they were asked if they believed the city could return to chaos again.

The debate about “Sicario” has “opened up the wound,” said Pérez, the MBA student. She said she would probably go and see the movie out of curiosity. “It’s just a piece of art,” she said. “But it hurts.”