SAN FRANCISCO (KPIX 5) — A smartphone app designed to track crimes as they happen just got a $12 million influx of investor cash.

It’s now launched service in San Francisco, but not everyone thinks this is a good idea.

A promotional video shows how the Citzen app works: Citizen employees listen to police scanners and when something happens, push out an alert through the app with the details.

Lea Artz with Citizen says, “When you see sirens fly past you or you hear a helicopter overhead and you don’t know what’s going on, that’s where Citizen comes in.”

Users in the area are then encouraged to post information to the crime alert, like uploading pictures or videos.

“We are actually following the story all the way through. So you’re getting the initial crime, then you’re getting every single update that’s relevant to you, until hopefully the incident has closed or has stopped,” Artz said.

Kpix 5 law enforcement analyst Howard Jordan is a former chief of the Oakland Police Department, and he says the app isn’t helping anyone.

“It creates a lot of hysteria, I think it promotes vigilantism,” Jordan said. “I don’t find that it will be of any useful purpose to law enforcement in terms of helping them reduce crime or make a community safe.”

Jordan says most people don’t have enough training to know if it’s safe to be at a crime scene, which could put officers and the public in danger.

“If there’s something in progress, then we want citizens not to be in harm’s way,” Jordan said.

But representatives with Citizen say safety is the top priority.

“We made it really clear in our terms of service that nobody using Citizen should be disrupting law enforcement, disrupting any active scenes,” Artz said.

The Citizen app is only working in San Francisco right now, but the company hopes to expand service to all of the Bay Area within the next few months.

We reached out to the san Francisco Police Department to see what officers think of the app, but they declined to comment.