At 8:07 p.m. on Monday evening in San Francisco, a man was spotted shooting a gun at streetlights. Twenty minutes later, an outdoor trash fire broke out in another part of the city. A few miles south, a KFC employee allegedly assaulted a co-worker with a chair, and then 20 bikers were reportedly involved in a brawl.
It's a typical hour in the San Francisco Bay Area as seen through Citizen, the real-time crime and fire alerting app that uses a smartphone's location to share updates about incidents happening nearby. Its alerts ping mobile devices daily in New York City, San Francisco, Baltimore and starting Tuesday, Los Angeles.
Using a combination of human employees and technology, Citizen scans hundreds of public-safety radio bands 24-hours a day in the major cities where it's deployed, sometimes by playing audio at three times the speed. It filters out what it deems non-essential and sends the information as short, factual alerts to everyone within a quarter mile of the incident. The app updates with a list of details as they roll in and lets people nearby take live video or comment with information.
Some local governments and police departments have their own alerting apps, and sites like Nextdoor are filled with user reports of incidents. But what makes Citizen different are its sources, the volume and speed of its text updates. It's closer in spirit to police scanner [cnn.com] apps.