CHICAGO–It’s summertime on the South Side of Chicago, and the sirens never seem to stop. In neighborhoods with names like Little Village, Back of the Yards, and Dolton, squad cars and ambulances scream day and night past shuttered storefronts and boarded-up houses.

Welcome to the one of the most violent cities in America.

There were 764 homicides here in 2016, according to a recent study by the University of Chicago Crime Lab. That’s a jump of more than 50 percent from the previous year, with most of them occurring in poor “ghetto” communities on the South and West Sides.

All that killing is fueled, at least in part, by the city’s booming drug trade.

Native poet Carl Sandburg once dubbed his home town “Player with Railroads and the Nation’s Freight Handler.” Add one of the country’s busiest airports and a cluster of major highway arteries to all those railroads and you get what DEA agent Mark Giuffre, of the Chicago Field Division, calls a “logistical hub” for narcotics trafficking.

“ The cartels supply the narcotics to the violent Chicago street gangs,” Giuffre tells The Daily Beast. “ Illicit drug smuggling [and] transportation groups are selling their services to any cartel willing to pay for them.”

Shipments of heroin, cocaine, and crystal meth pass through the Second City on their way to neighboring states like Wisconsin and Indiana.

One popular drug-running route is I-290, which connects to Milwaukee and points west, and is known locally as the Heroin Highway.

“ Much of what comes here doesn’t stay here,” says Giuffre, whose full title is Assistant Special Agent in Charge. He refers to the Toddlin’ Town as a “lucrative market” and “transshipment point” for illicit substances to reach whole swaths of the Midwest and Eastern U.S.

Wholesale vs Retail Slaughter

Most of the drug routes originate on the Southwest border with Mexico, in places like Tijuana and El Paso. The most common method for shipping dope north is overland by road, often in tractor-trailers, busses, or personal cars equipped with hidden compartments.

Mexican Drug Trafficking Organizations (DTOs) operating cells in the U.S. typically refrain from acts of overt mayhem, so as not to call attention to their presence. Giuffre describes these cells as disciplined networks made up of the friends and family members of cartel operatives back home.

“ They don’t distribute a single kilo without specific instructions,” he says.

The once-dominant Sinaloa Cartel has been weakened in Chicago, due to the capture and extradition of former boss Joaquín “El Chapo” Guzmán. That power shift has allowed other groups like The Jalisco New Generation Cartel (CJNG), Los Rojos, and Guerreros Unidos to move into the Chi-town marketplace.

In Mexico, the competition to replace the Sinaloa Cartel has led to a feeding frenzy among rival DTOs, sending the country’s murder rate soaring to the highest level since the country’s Drug War began in 2006.

Last year also marked a two-decade high for homicides in Chicago, but Giuffre says it’s “not cartel warfare” in the Windy City.

Instead it’s the rival street gangs in Chicago supplied by the DTOs that are engaged in deadly turf battles.

“ It’s all about territorial beefs between gangs,” says Adam Isacson, a security expert with the Washington Office on Latin America (WOLA), in a phone interview with The Daily Beast.

Some of the factional gang killings occur during “fighting for territory for local drug sales” on corners and city blocks, while others are rooted in “simple hatred,” he says.

The cartels might be slaughtering each other over shipping corridors in Mexico, but on the U.S. side of the border, the “guys doing wholesale are less violent than the guys doing retail,” Isacson says.

Sturm and Gang

The DEA estimates there to be about 100,000 active members of crime groups in Chicago, which it lists as “the street gang capital of America.” Some of the most powerful groups are the Gangster Disciples, the Vice Lords, and the Latin Kings. But within these umbrella organizations there can be schisms and rivalries. In all there are some 700 factions, and many of them use coded handshakes, colors, or patterns of dress to i.d. each other—or spot outsiders in their neighborhoods.

Handguns are the most common weapon for gangsters, because they’re cheap and easy to hide under loose clothing. But they’ve also been known to set up ambushes using assault rifles capable of piercing police body armor. Assaults on funerals and memorial services for fallen members of rival outfits are a favorite trick, as the perceived enemies are then gathered in large numbers, often unarmed and in the open.

Many of the gangs operate out of so-called “trap houses,” which are foreclosed or abandoned homes where they hold meetings and repackage or distribute narcotics. Other trap houses are occupied for more innocent purposes, such as shelter or sleeping (poverty and homelessness are common among gang members).

Guadalupe Cruz, a social worker and teacher at the University of Illinois at Chicago, says that for many young people, gang involvement is “generational” due to young people having “parents [who] were also involved in the street life.”

The culture is so ingrained that it becomes a “social norm to wear certain colors, or not to cross certain streets,” Cruz explains, in an interview with The Daily Beast.

“ They’re exposed to violence so this is what they know,” says Cruz, who runs an after-school mentorship program in Little Village, about a mile from the Heroin Highway.

“ When someone is shot and on the floor dying, they don’t react,” Cruz says. “There’s no reaction that something is wrong, or that it shouldn’t be like this.”

Fighting Back

One person who does know it shouldn’t be like this is Chicago-based martial artist Darrel Taylor. On a stifling hot night in late July, Coach Taylor takes a few minutes away from training aspiring fighters at a gym on the South Side to speak with The Daily Beast.

“ As a black man in America you don’t have too many positive role models,” says Taylor, 32. “I try to be the best coach I can. If they come to me with any life problems, I help them out to the best of my abilities.”

Taylor instructs his charges in multiple forms, and tonight’s focus is boxing. The Sweet Science and other martial arts teach discipline and a solid work ethic, as well as “problem solving on the go,” he says.

The gym where Taylor trains tonight sits across from what was once a K-Mart and is now just another empty shell. Inside the club a half-dozen fighters wait in line to “work the pads” with their coach. Most of them will use gloves and other gear he’s brought for them.

“ Combat sports helps them to develop mental toughness, so they’re ready when life throws them a curveball. If you can do this you can survive the life.” Taylor encourages his pupils to “stay in school with a purpose,” although he acknowledges that many of them see professional fighting as a way to escape poverty, “of making it out.”

Taylor also credits his martial arts background for having kept him on the straight and narrow.

“ Most of my friends growing up were involved in that [gangster] life,” he says, raising his voice over the steady thumping of fighters on the heavy bags. “I always told them, ‘I can’t do that—I’ve got practice.’”

Addiction Affliction

Despite the efforts of volunteers like Cruz and Taylor, Chicago was last year’s U.S. leader for homicides committed. Unfortunately, that’s not its only dubious distinction.

“ Chicago is number one in the nation for heroin overdose related emergency room visits, and number one in the nation for people seeking publically funded treatment for heroin dependency, ” according to DEA Agent Giuffre.

He attributes that in part to an increase in street-level purity by about 30 percent in recent years, as well as the cartels’ penchant for cutting their smack with the synthetic opioid fentanyl, which can cause even seasoned junkies to O.D.

Giuffre, who has more than thirty years of narcotics law enforcement experience, accuses the cartels of “profiting off the misery of addiction.”

And when it comes to heroin, their profits are going up. The Chicago DEA Field Office’s seizures over the last three years have climbed by 300 percent—yet street prices of the drug have continued to fall.

A single-serving size bag of heroin—often called a “blow”—in Chicago sells for about $10.

A “jab” is 10 blows and usually goes for about $100 (normally a person ordering a gram-sized jab will get two or three extra blows in their bag.)

A kilogram of arm candy, meanwhile, runs for anywhere between $48,000to $55,000, as the price can shift down for bulk purchases.

“ It looks like from the DEA numbers that Mexican heroin production has tripled since 2013, which would explain why supplies in Chicago have increased similarly,” says WOLA’s Isacson.

The surge in poppy cultivation in Mexican states like Guerrero has been caused in part by the cartels’ shift away from marijuana, after legalization and decriminalization in the U.S. caused the price of weed to plummet. A steep rise in American demand for heroin has also contributed, as government crackdowns on prescribed opioids forces users to swap pills for the needle.

And the newly empowered Jalisco New Generation Cartel also “specializes in [heroin] and they’ve been eating Sinaloa’s lunch,” says Isacson, referring to the downfall of Chapo Guzmán’s old syndicate.

“ Seizures have been increasing at the border, but they haven’t tripled. So a lot more is getting through too.” Tunnels, cleverly disguised consumer goods, and even food packages are all tricks in the cartels arsenal for eluding customs inspectors.

“ It’s just so easy to conceal,” Isacson says.

City on Fire

Special Agent Giuffre’s team remains focused on “command and control of the cartels” using “a variety of efforts focused on cartel cell leaders.” His office is responsible for scores of successful indictments, including those against the infamous El Chapo and more than 70 of his co-conspirators.

The Chicago Police Department’s track record, on the other hand, isn’t so sterling.

Isacson, of WOLA, says “Chicago policing efforts” are also to blame for the deteriorating security situation.

“ The relationship with the community is bad,” he says, and begins to tick off a list of complaints that include slow response times, charges of police killings and torture of suspects, even allegations that a “police death squad” was at work in the city. (The Chicago police department did not respond to interview requests for this story.)

Those factors also combine with “poor outreach to the south and west sides of Chicago which are both black and Latino,” Isacson says. “It’s a city with a lot of gangs, but a lot of cities have a lot of gangs. Other cities have meetings with communities . . . I don’t know why they’re so resistant to change.”

UIC teacher Guadalupe Cruz, who also works for the NGO Cure Violence in Honduras and Mexico, says the habit of neglecting certain communities goes beyond just local law enforcement. And that this collective indifference to marginalized neighborhoods is directly tied to the recent spike in homicides.

Many young men turn to hustling drugs on the street for the simple reason that “there are no jobs, but they still have to feed their kids,” Cruz says.

“ Of course violence is going to go up when they don’t have anything else to do.”