What if a murder could be predicted? What if police could intervene with the future victim or future killer? In Chicago, an experimental computer program is trying to do just that. It's called predictive policing and the city is counting on it to ease some of the worst gun violence there since the 1990's. There were 650 murders in the year just ended, that's more than New York City and Los Angeles combined. The computer program spits out the names of those most likely to shoot or be shot. Police say the results are uncanny. But it's what Chicago does with the data that is saving lives. Ask Ernest Smith, who, according to the computer should be dead or in prison by now.

Ernest Smith: I got enemies. You know what I'm saying? And they don't like me, you know? I mean, it's all a part of growing up in Chicago.

Ernest Smith's tattoo CBS News

Ernest Smith was a trigger pulling, drug pushing, menace to Chicago's west side.

Scott Pelley: One of the reasons you had enemies was you joined a gang.

Ernest Smith: Yeah. I was a gang-- I'm a gang member.

Scott Pelley: That's a gangster disciples tattoo on your hand?

Ernest Smith: Yes. It's a six. You know? Yeah.

"The violence is unacceptable, it's not gonna be tolerated. We will stop you if you make us; we will help you if you desire the help."

Smith was a star on the police department's 'strategic subjects list' which attempts to rank Chicagoans most likely destined for solitary or a cemetery.

Scott Pelley: You were in the top 1 percent. In the risk group that they're following.

Ernest Smith: Yeah. I know. I could believe it because, you know, I used to be wild, I was, man, real wild you know.

Chris Mallette: The goal of this operation is: Keep people alive. That's number one. Number two, keep 'em outta prison and jail.

Chris Mallette runs the program that has, so far, saved Ernest Smith.

Mallette is executive director of the Chicago Violence Reduction Strategy.

Chris Mallette CBS News

Chris Mallette: The violence is unacceptable, it's not gonna be tolerated. We will stop you if you make us; we will help you if you desire the help.

Mallette has assembled a coalition of cops, social workers, ministers and moms.

Chris Mallette: We're looking to get people to put guns down, we're looking to get people to stop pulling triggers. And by "we," I mean the collective partnership of local, community folks who are partnering with local law enforcement to try to get this done collectively.

It starts with that computer program, a $3 million experiment run by the Chicago Police and the Illinois Institute of Technology.

Commander Kenneth Johnson: We try to identify the subjects who are most at risk.

Commander Kenneth Johnson explained that everyone arrested in Chicago is assigned a risk score of zero to 500. Commander Johnson showed us the file of Shaquon Thomas, someone not unlike Ernest Smith, whose history of arrests added up to a risk score of 500.

Scott Pelley: What are the things that go into that?

Commander Kenneth Johnson: Well, some of the things that go into the risk model is who they're associated with, their arrest history, and also whether or not they've been a victim or they've been an offender of a violent crime. How many gun offenses they've been involved in, those are all factors that go into it.

Commander Kenneth Johnson: Here he is fighting a police officer, now unlawful possession of a handgun.

Scott Pelley: And then here at the end, first degree murder, and he's the murder victim.

Scott Pelley: End of timeline.

Commander Kenneth Johnson: At 22 years old.

Commander Kenneth Johnson during a strategy visit. CBS News

This is what Commander Johnson does with the data. The heart of the Chicago Violence Reduction Strategy is to personally visit those that the police believe are at high risk of being a shooter or a victim. The visit is based on the computer score and other factors including recent shootings among friends and enemies or taunting in social media which is a big driver of violence these days.

Johnson (Visiting Aaron Green): You've been shot before right? How long ago was that?

Green: Like a week and a half, two weeks.

First, 21-year-old Aaron Green got a blunt letter from the superintendent of police which reads, in part, "if you engage in gun violence, rest assured, you will be subject to arrest and prosecution to the fullest extent of the law." But then, neighbors and social workers step in to offer a way out of gang violence.

Chris Mallette: And the message is, "Listen, we love you, we value you and we need you."

Scott Pelley: We love you?

Chris Mallette: We love you, absolutely. We love you, we value you and we need you. But here's the catch: We need you in your rightful place.We want to restore you to your rightful place in our community.

Scott Pelley: When they came to your home, what did you think? What was the first thing you thought when you saw that police officer out there?

Ernest Smith: Oh, man. I thought I was dealing with something else. I thought they came back from something I did a way back in the day. I was like, Aw, man. They done finally got me.

Scott Pelley: What did they say to you that day?

Ernest Smith: They had a man with them and they wanted to talk to me about this program, you know, to help me get my life together.

The man who came to talk to Ernest Smith was Charles Perry.

Charles Perry and Ernest Smith CBS News

Charles Perry: So what I tell 'em is, "I used to be you."

Scott Pelley: What did you do?

Charles Perry: I sold drugs. I shot people. I mean, you name it, I did it.

After 19 years and 29 days in prison, Charles Perry became one of the social workers essential to the Chicago strategy.

Charles Perry: Young people believe that they not worth anything. Whatever they got in they immediate surroundings is all they are, all they'll ever be. And it's so far from the truth.

Scott Pelley: But how do you convince a young man who's known nothing else in his life that he is somebody?

Charles Perry: It's not my job to convince you. It's my job to plant the seed. 'Cause nobody else has planted a seed in you other than destruction and death.

The social worker takes his client by the hand; walks him through the DMV to get a driver's license, helps him with clothes, takes him to job training, and helps him find work.

"They just want somebody to show that they love 'em, you know, to tell them that they love 'em, let 'em know that they life is important, too. Somebody care about 'em."

Chris Mallette: We call it the big small stuff. There's some stuff to us that's just small stuff. Go get your license. Go get an ID. Go finish your degree, which is small stuff to the majority of us, I would say, but it becomes very big stuff to guys who are caught in this lifestyle, who've never engaged in that way.

Ernest Smith didn't have an ID.

Scott Pelley: Why did the ID matter so much?

Ernest Smith: Because you learn you can't do nothing in life without identification. When I got that ID, it's like, man, like a huge weight got lifted off my shoulders, you know? I felt like a member of society again.

An ID and Charles Perry got Smith his first job at the age of 31. For a while he worked part-time in a kennel. Now he's looking for full-time work.

Ernest Smith: Man, it was like heaven, you know? Even though I was a drug dealer, you know, like, I always, kind of, had money, but it feels different when you work for it. I wanna keep working. I don't ever wanna go back to the streets.

Scott Pelley: When you come into someone's home and say, "We're here to help you," how often do those guys believe you?

Chris Mallette: Well, if you look at who's reaching out for help, one out of three will reach out for help.

Scott Pelley: One out of three?

One of the obstacles to success is fear and loathing of the cops. Chicago Police have an infamous history of brutality. So the violence reduction strategy enlists the neighborhood.

Donna Hall: They just want somebody to show that they love 'em, you know, to tell them that they love 'em, let 'em know that they life is important, too. Somebody care about 'em.

Donna Hall has a way of melting ice. She's delivered mail in her neighborhood for nearly 20 years. But her heaviest burden she carries, special delivery.

Donna Hall CBS News

Donna Hall: I'm not the person that I used to be. I was angry. I was mad at God. But in all reality, I was mad at Marshall. I was mad at him for leavin' me.

Her son Marshall left in 2013. That's him, at right, in the parka. A surveillance camera recorded the end of his life.

Donna Hall: "Boom. Boom. Boom." And he falls.

Shot for no known reason, by someone unknown. Donna Hall helps lead "the Sisterhood" a movement of moms of the murdered.

Donna Hall: We the community, we have to get on the front line. I don't like to march. I'm not marchin'. Because you can't hear me in a crowd.

Scott Pelley: All about meeting people one on one.

Donna Hall: Because if I'm sittin' here, we can hear each other. You receivin' it better. 'Cause I'm tellin' you what I went through. It's real. This pain is real.

Scott Pelley: Don't some of 'em just look at you and think, "I can't wait for this lady to get outta my house"?

Donna Hall: Probably so, a lot of 'em. A lot of 'em do. But when, when it's over, I stop 'em right there. And I tell 'em…

Donna: Gimme a hug, I'm a hugger.

Donna Hall: And I tell 'em, "Just, if you gotta close your eyes, just picture your mama standin' right here for a minute. You're breakin' my heart. It would break my heart if somethin' happened to you.

But not even a mother's plea is enough, most of the time. Jamal Cain is one of the roughly 66 percent who refuse help.

Scott Pelley: The cops put you on their list of people likely to shoot or get shot. Were they right about you?

Jamal Cain: Yeah. I guess. I've been shot six times.

When the Violence Reduction Strategy Team came to his home, he saw the cops and he hid. His grandfather took the social worker's card.

Jamal Cain: I just looked at it and threw it down. 'Cause I had no intention of callin' them. I never did call because I don't think the police wanna help me.

Scott Pelley: You regret that now?

Jamal Cain: Not really.

Scott Pelley: You still don't believe it?

Jamal Cain: Nope.

Jamal Cain CBS News

When we saw Cain he was in jail on a gun possession charge.

Jamal Cain: I grew up on the bad neighborhood, but that-- that don't make me bad. Just make me stuck.

Scott Pelley: "Stuck"? What do you mean?

Jamal Cain: I'm not necessarily a bad person. It's just the things I do may be bad, if you grow up and you see everybody sellin' drugs, gettin' money the fast way, you wanna do it. It don't necessarily mean you wanna be violent. Violence has come along with the way life that we live.

Chris Mallette: We don't necessarily consider these guys to be bad people. They could just be very dangerous at times. And there's a bit of a difference.

Scott Pelley: Oh, what's the difference?

Chris Mallette: Well, I think the difference is if people are driven to what they think is their barrier and their breaking point, what are they willing to do, When you see them out of that element of just engaging on the street, you see 'em as fathers, you see 'em as sons, you see 'em as community members.

Scott Pelley: You know a lot of people watching this interview right now are thinking, He's coddling criminals. You need to lock these guys up forever. And the problem will be solved.

Chris Mallette: I think some of 'em need to be locked up, but here's the reality, Scott, they're gonna keep coming back. You solve the problem by engaging and interacting with individuals.

But it's tough for individuals to break from a gang. Just wanting out doesn't change the neighborhood. Ernest Smith was sorely tested when his former girlfriend, the mother of his child, was murdered.

Ernest Smith: Man, I was hurt. I was mad. You know, I was ready to get out there and go back to my old ways.

Scott Pelley: Before that home visit with the police and with Charles, you would've gone out to find somebody to shoot.

Ernest Smith: Oh, yeah. I would've went crazy. I would've snapped out.

But he didn't. And he hasn't been arrested since joining the program a year ago.

Scott Pelley: But how hard is it to stay out of crime?

Ernest Smith: Really, to keep it honest with you, it ain't. We basically, we make up excuses to go back. We make up excuses to go do the things we wanna do. You know, I got demons. They fight with me. You know, like you broke. Go take this. Go do that. But I learned to wait and be patient, you know, and ever since good things been happening and coming through the door for me.

And Chicago will have to be patient. It's taken four years for the violence reduction strategy to visit nearly 1500 people. Of them, 78 percent have no new arrest for a violent crime.

And in 2017 shootings were down 21 percent.

Scott Pelley: Can the violence end?

Charles Perry: Will it end? Yes.

Scott Pelley: How do you get there?

Charles Perry: We're doing it to ourselves. All we gotta do is stop ourselves from doing it. There's no one riding in on a white horse to save us. The savior is right there in the community. They right there.

Produced by Aaron Weisz. Associate Producer, Chrissy Jones.