In our Edward Snowden era, we think of “mass surveillance” in terms of national security more often than in terms of local law enforcement. But one sort of technology used at the Fresno Police Department in California is shifting that discussion.

Fresno’s Real Time Crime Center is a high-tech hub full of monitors, camera feeds and two billion scans of vehicle license plates and locations nationwide. Working alongside all of this is what might be the most interesting piece of tech there: the software Beware. Built by security company Intrado, a subsidiary of West Corporation, the software collects data like arrest reports, property records, commercial databases, deep Web searches and social media posts to calculate a person’s so-called threat level.

While few departments will delve deep into the technology they’re using, The Washington Post was able to get an inside look into the Crime Center and the Beware technology.

The Post says Fresno is one of the first police departments in the nation to test Beware. When officers respond to calls, the software works quickly and quietly in the background. It automatically runs the address, returns “the names of residents and scans them against a range of publicly available data to generate a color-coded threat level for each person or address: green, yellow or red.”

How the algorithm calculates threat scores is something Intrado won’t reveal — not even to the police.

"Beware is a tool built to help public safety agencies inform first responders about the environment they may encounter when responding to a 9-1-1 call," an Intrado spokesperson said in an email to Mashable.

"When a first responder receives a request for assistance during a 9-1-1 event, they have a short window of time to collect information. Beware works to quickly provide them with commercially available, public information that may be relevant to the situation and may give them a greater level of awareness. Beware is one of many tools available to first responders to provide situation-specific information during a 9-1-1 response."

Other than that, the few details we do know are on the company’s website. Here’s a brief description:

Beware uses a patent-pending, web-search algorithm to scan massive amounts of commercial data and presents it as actionable intelligence, complete with threat scores in an easy-to-read headline format-all within seconds of an initial query.

“Our officers are expected to know the unknown and see the unseen,” Fresno Police Chief Jerry Dyer told the Post. “They are making split-second decisions based on limited facts. The more you can provide in terms of intelligence and video, the more safely you can respond to calls.” The Fresno police department did not respond to Mashable's request for comment in time for publication.

Considering the elusive and pervasive nature of Beware, there are of course concerns from residents.

Fresno civil rights lawyer Rob Nabarro told the Post he worries the system might mistakenly increase someone’s threat level by misinterpreting social media activity and affect how strongly police respond.

One example was brought up during a Fresno City Council hearing on Beware in November. A council member mentioned a local report that a woman’s threat level increased after she tweeted about a card game called “Rage,” which could be a word Beware picks up in social media.

Dyer said the score doesn’t trigger a specific police response but are instead used to provide more information that might be relevant to officers before they arrive on scene. Dyer wasn’t immediately available for an interview request from Mashable.

Councilman Clinton J. Olivier wanted to test Beware and asked Dyer if he could run his threat level right there, during the hearing. The scan for Olivier returned green, the Post reports, but his home came back as yellow. A police official said it could have been because of someone who previously lived at his address.

“Even though it’s not me that’s the yellow guy, your officers are going to treat whoever comes out of that house in his boxer shorts as the yellow guy,” Olivier said. “That may not be fair to me.”

After the hearing, Dyer said he wanted to make changes in response to the various concerns, and he’s working with Intrado to turn off Beware’s color-coded rating system and possibly the social media monitoring.

It’s hard to not be skeptical about Beware. Sure, the software seems to provide a wealth of information quickly, but we can’t anticipate how officers will interpret and use that information — like in the case of Olivier.

The Atlantic’s report of Beware also considered a few ways the software could be a flawed tool:

The algorithm could assign an elevated threat level to individuals who have social-media accounts registered under names typically given to black or Hispanic people. It could assign an elevated threat level based on tweets or Facebook posts that offer constitutionally protected speech that criticizes police officers or police unions. It could disadvantage low-income people by assigning an elevated threat level to their addresses based on the behavior of past tenants in their high-turnover apartments, while richer folks in single-family homes are less often miscast.

While it's reasonable for law enforcement to embrace technology, it should still be approached with a certain level of skepticism. And since Intrado hasn’t been very transparent about exactly how Beware works, we’re only left to ponder the possibilities.