If you have not seen the video, beware. It is disturbing.

Three teens or young men walk up to a convenience store on the South Side. One of them pokes his head in the door to see who’s there. Then all three pull guns and fire repeatedly into the store.

They kill a young woman. They wound four other people.

Now here’s the thing:

This happened Tuesday and the police are still looking for the shooters. We don’t even know their names yet. But you can bet good money that this shooting, like so many other shootings in Chicago, had everything to do with gangs.

Editorials

Street gangs are one of the great scourges of Chicago. They are a reason our city suffers from such a high rate of violent crime — along with all the other explanations we constantly lament, such as the easy availability of guns, the illegal drug trade, poverty and unemployment.

The Chicago police, whom we ask to protect us, need tools to fight the gangs.

All of this, we suppose, is a long-winded way of getting to the point of this editorial: We firmly believe the Chicago Police Department should maintain a gang member database, so long as the list is rigorously fair and monitored. It’s just common sense.

We support the creation of a new and more carefully crafted CPD gang database recently announced by Acting Police Supt. Charlie Beck and endorsed by Mayor Lori Lightfoot. The new database, called the Criminal Enterprise Information System, will launch in the next six to 12 months and will aim to ultimately replace CPD’s existing gang database.

In the past, we have written editorials condemning the police department’s previous gang database, which was a farce. We argued that the database should be cleaned up or chucked.

There were names on the list of people who had died years before. There were names of middle-aged men who had left the gang life decades ago. There were names of people who had never been in a gang. There was a disproportionate racial makeup to the list — white gangs seemed to get a pass.

There was no appeals process for getting one’s name off the list. And the list could be viewed by third parties who had no business seeing at it, such as employers.

But thanks to a federal lawsuit, a scathing review by City Hall Inspector General Joe Ferguson and — we would like to think — public pressure created in part by editorials such as ours, CPD under Beck has overhauled the rules.

The database will be more focused now, with a multilevel process for determining whether a name goes into it. It will include an appeals process overseen by the civilian Police Board. The names of people who have had no contact with law enforcement for five years are to be automatically removed.

And only law enforcement personnel with a legitimate need to see the list, such as detectives working a criminal investigation, are to be granted access.

Given all this, we frankly marvel at the thinking of local activists, supported by some aldermen, who think there should be no gang database at all.

As if the presence of violent gangs is not why so many Chicagoans are afraid to step outdoors. As if gang members are misunderstood ragamuffins.

There will always be a risk that a database such as this will be abused. Constant vigilance — by the Police Board, civil liberties groups and the media — remains essential. The true integrity of the new database will be better assessed in a year or two.

But when three men shoot up a convenience store, killing an 18-year-old nursing student, there is every reason to suspect this was gang-related — because we’ve seen it before. A 2017 study published by the University of Chicago Crime Lab showed that an overwhelming majority of shooters in Chicago have known gang affiliations.

We want the police to track down and arrest those killers.

A gang database, carefully crafted and monitored, is an important tool of this essential police work.

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