Editor’s note: To memorialize the victims of Chicago’s most violent year in two decades, the Chicago Sun-Times wrapped Sunday’s print editions with 618 faces of the 780 people murdered citywide in 2016 — every victim’s photo that the newspaper could obtain. Columnist Mary Mitchell offers her take on steps to address the city’s violence problem here. To read more stories of homicide victims, go to the Homicide Watch Chicago website: homicides.suntimes.com.

They were murdered on one of the most sacred days on the Christian calendar.

Two of the victims were brothers: James Gill, 18, and Roy Gill III, 21.

Jerry Thomas, 22; Fabian Ortega, 18; and Niko L. Walker, 21, also were killed in various parts of the city on Christmas Day.

The Gills were gunned down on a porch in Chatham. The other victims were killed in West Humboldt Park, Gage Park and South Shore, in the shadows of hard-working people trying to raise families.

In the waning days of 2016, the fallen fit the profile of the city’s murdered. They were young, male, black and Hispanic.

To many, the faces staring out from the collage of victims murdered in 2016 have no connection to them.

But take a closer look.

Nykea Aldridge — a mother of four and Chicago Bulls star Dwyane Wade’s cousin — was pushing her toddler in a stroller when she was caught in gang crossfire near her Parkway Gardens home.

Ronald L. Allen, 73, was a successful insurance agent and west suburban businessman, shot to death while driving in North Austin, an area where he grew up.

In a sea of black and brown faces, 16-year-old Christian Bandemer’s stands out. The white teenager was killed in an accidental shooting blocks from U.S. Cellular Field in Bridgeport. And then there’s 25-year-old Aaren O’Connor, also white, struck by a stray bullet as she was sitting in her car talking on her phone in Pilsen.

Every homicide is abhorrent, but there were those deaths that left us speechless.

Twins Edward and Edwin Bryant, 17, came into the world together and left together, killed in a drive-by shooting early on a Sunday morning in the Old Town neighborhood.

And while the vast majority of the 780 homicides were gun-related, domestic violence, child abuse and stabbings also played a role in boosting Chicago’s murder rate to a jaw-dropping level.

A 50-year-old grandfather allegedly killed infant Katana Symone Greenlee using blunt force trauma. An enraged ex-fiancée allegedly stabbed Julia Martin, 28, to death in a murder-suicide.

Politicians continue to rail about lax gun laws and the criminal justice system’s failure to keep repeat gun offenders off the street.

But something insidious has crept into our midst.

Nearly 20 years ago, acclaimed sociologist Elijah Anderson warned of its coming in his 1994 study titled “Code of the Street: Decency, Violence and the Moral Life of the Inner City.”

“The inclination to violence springs from the circumstances of life among the ghetto poor — the lack of jobs that pay a living wage, the stigma of race, the fallout from rampant drug use and drug trafficking, and the resulting alienation and lack of hope for the future,” wrote Anderson, a professor of sociology at Yale University.

The code of the street has not changed, but other components of daily life in distressed neighborhoods have.

“The gangs are more splintered today, but also gang members have social media at their disposal. This is one reason why you can have so many killings at one time, say over a weekend, over Christmas,” Anderson said.

“At one point, gangs were better organized, which limited the violence and the killing. Today, more young people are freelancing,” he said.

Anderson also noted the “declining respect” for the civil law and increased dependence on “street justice.”

“Street credibility becomes the coin, but this is high maintenance, and is something not established once and for all, but must be reinforced repeatedly in deeds,” he said.

A draft report on the city’s year-end homicide rate by the University of Chicago Crime Lab concluded that a “sudden, large and seemingly sustained increase in gun crime occurring in public, involving teens and men in their 20s and 30s in a small number of distressed neighborhoods on Chicago’s South and West Sides.”

Researchers could not determine the cause of the increase with available data, but they don’t rule out the role the structure of gang activity and social media could have played.

Additionally, we can’t talk about reducing the violence without talking about putting a greater emphasis on creating more living-wage jobs.

Anderson argues the inner city has its own economic system based on “low-wage jobs, government assistance, and hustling, bartering and loaning money, although the drug trade is the lucrative element of the underground economy.

“Because of the economy, there are a host of transactions. These transactions, or exchanges, are engaged in without the benefit of civil law. People don’t sue others for their money. They are more likely to get in someone’s face to demand payback. When the money is not forthcoming, there is trouble or violence,” he said.

“It goes back to an eye for an eye and a tooth for a tooth. People deal with each other without resulting to civil law,” Anderson added.

We were all appalled when U.S. Rep. Danny Davis’ grandson, 15-year-old Javon Wilson, was shot in the head and killed after an argument over basketball shoes. Two juveniles were charged with the murder.

But the tragic incident fits Anderson’s theory.

Most of us would agree that we are a tale of two cities — one thriving where most white people live — one economically deprived where most black and brown folks live.

But too many of us don’t see how the alienation of low-income black and brown people has attributed to the chaos we are now witnessing.

That’s one reason why the Rev. Michael Pfleger led a New Year’s Eve anti-violence and peace march along the Mag Mile rather than on the streets where most of the murders have occurred.

We are among the most segregated cities in America — and that’s become a big part of the problem.

“The discrimination contributes to the alienation that a lot of black people feel, and it encourages young people to join gangs and make it any way they can,” Anderson said.

There are no easy answers, but a lot more of us have to be willing to make Chicago a place of opportunity for everyone.

“Young people need jobs. They need opportunity and an incentive to go straight. Economic opportunity is really basic,” Anderson said.

For instance, cranes are everywhere in Downtown Chicago, where white workers scurry in hard-hats and steel-toed work boots.

But on the South and West sides, large tracts of land are blighted and commercial properties are boarded up.

Here, young black men huddle on corners — rain or shine — day and night.

Some of them will live to turn 30.

So many others will not.

You may not care what happens to them.

But look at faces of the murdered.

What has happened to them and their families is happening to us.