On a recent Saturday night, Jackie Eicholz heard sirens — lots of them. Eicholz, who lives in California’s Santa Cruz County, got out her phone, opened up a pair of police-scanner apps (5-0 Radio Police Scanner and Police Scanner Radio & Fire) and began trying to piece together what was happening. 

The public-relations worker overheard chatter about a few peaceful protesters, but also about police heading to various locations, and a troubling reference to a hostage-negotiation team. Eventually, she found out that the sirens had nothing to do with protests. 

Law enforcement officers were responding to calls about an active-duty Air Force staff sergeant with bomb-making equipment, who allegedly went on to shoot and kill a sheriff’s deputy that night before attempting several carjackings and eventually being subdued by a civilian. 

Since tracking the events of last Saturday, Eicholz has found another use for the scanners. 

“Now I’m trying to listen in on how they talk about protesting,” she said.

Eicholz and thousands of other Americans are turning to police-scanner apps as protests in response to the police killing of George Floyd in Minneapolis continue to rock the country. Crime-report app Citizen and encrypted-messaging app Signal are also seeing spikes in downloads as events unfold in people’s neighborhoods. Some of the apps saw downloads jump by more than 300% in the two weeks after Floyd’s death as protests for racial justice spread, according to Apptopia.

“Different events drive downloads for different apps,” said Adam Blacker, Apptopia’s vice president of insights and global alliances, who added that food delivery apps spiked at the beginning of the coronavirus pandemic.

Each of these types of apps serves a different purpose, and they can be helpful for protesters, residents and business owners trying to stay on top of rapidly changing situations. Here’s more about how each of these kinds of apps can be helpful, and what to keep in mind if you use them.

Citizen and Neighbors

Apps like Citizen and Neighbors, which is affiliated with Amazon’s Ring security cameras, can help users keep track of crime and police activity in their neighborhoods. Neighborhood messaging services like Nextdoor, as well as group pages on Facebook, can also help keep residents in the loop.

Of these, Citizen has seen the biggest spike, according to Apptopia. From the weeklong period ending May 27, during which a police officer killed George Floyd, to the weeklong period ending on June 10, the number of downloads jumped 325% to 306,000 total downloads. The app aggregates information on police activity from 911 calls and crime reports and sends them in alerts to users.

Ice cream shop owner Katie Wages lives in Emeryville, California, where looting hit shopping centers in late May. She’s been using Citizen to track where protests with crowds and a police presence are taking place. The app, she says, also gives her “comfort” that her business is safe.

Users should be aware that information shared with some of these apps can go to law enforcement, potentially involving someone in a police investigation. For example, many police departments partner with Ring to see information shared on the Neighbors app, and can use a portal to request Ring camera footage from residents. (Residents aren’t required to comply.)

Signal Boost

Telegram is the encrypted-messaging app with the most users in the US, but competitor Signal has seen a big spike in users over the past three weeks, according to Apptopia. From the weeklong period ending May 27 to the weeklong period ending on June 10, downloads of Signal jumped 185% to more than 192,300.

Encrypted messaging is useful for people who want to keep their text messages private, including protesters discussing how best to organize, said Cooper Quintin, a senior staff technologist at the Electronic Frontier Foundation. However, the apps have limitations.

Signal and similar services encrypt your messages as they travel along the internet to your contact’s phone. That means your phone carriers and your internet service providers can’t read them, unlike your regular SMS text messages, which are sent in plaintext. It’s important to remember, however, that the apps don’t protect messages on your device. Anyone who has access to your phone can typically read them. 

If you’re concerned about law enforcement or anyone else reading your messages if you get arrested or lose your phone, you need to take extra steps, Quintin said. Signal offers a disappearing-message feature, which deletes messages after a preset period of time after you’ve read them.

That makes text messages “much closer to something like actually whispering to your friends,” Quintin said.

Police scanners

Police-scanner apps rebroadcast police radio chatter, which is typically available to anyone with the right radio equipment. The apps as a category are seeing a big boost, according to Apptopia. Scanner apps saw 1.2 million downloads between May 28 and June 3. In the following weeklong period, downloads dipped slightly to just under 1 million, but that’s still 311% higher than before protests began. One of the top two apps in terms of number of downloads is called Police Scanner, Live Police. The other is called Police Scanner Radio & Fire.

Scanner apps can alert protesters to when police plan to use tear gas, rubber bullets or other projectiles. They can also tell residents like Eicholz when something really serious is happening outside their doors. 

They do tend to have a lot of ads in their free versions. Eicholz, who tested multiple apps before settling on two she found useful, said the ads created an uneven experience. Users can always pay for the ad-free version, or opt to purchase a dedicated police scanner radio.

Another challenge is understanding what all that police chatter really means.

There’s “not a ton of context,” Eicholz said, “and some of the codes I had to look up.”