Suzanne Kreiter/Boston Globe/Getty Images

A surveillance camera caught Kendra Tatum's attention.

Mounted on a pole in a St. Louis commercial district, the camera could have a line of sight into MoKaBe's, a coffee shop where local activists like to get together.

An activist, Tatum finds herself keeping track of devices that police could use to keep track of her. The city's police department maintains a hub called the Real Time Crime Center that combines data from surveillance cameras, automated license plate readers and microphones that listen for gunshots to help police respond to events in real time. But it could also use this technology to track groups that plan protests against the police, Tatum worries.

"It's hard to draw the line with not wanting to be paranoid, but also being wise and conscious about the work I do," Tatum said.

Some clarity might be on its way. Cities around the country have passed laws that would create a public process for deciding how police can purchase and use surveillance technology. Police departments in 13 jurisdictions including Seattle, Oakland, Santa Clara County, Nashville and Cambridge have seen similar laws pass. More states and cities, including St. Louis, are weighing whether to follow suit.

The St. Louis Metropolitan Police Department declined to comment on the pending bill and didn't immediately respond to a request for comment on concerns it could use surveillance tools against activists. The department confirmed it operates a surveillance camera at the intersection Tatum named.

Now playing: Watch this: Backlash grows for police use of facial recognition (The...

Throughout the country, It's hard to know just how many surveillance tools police are using, because of the secrecy that has surrounded their use. The federal government alone has more than 330 cell site simulators, which detect nearby smartphones, according to an investigation by the US House Oversight Committee in 2015, but it's unknown how many of the devices are used by state and local police departments. An investigation by the New York Civil Liberties Union found that a state agency had funded the purchase of 422 license plate readers, with at least one in every county in the state. Other agencies in the state had also purchased the devices. According to Reuters, 9,000 surveillance cameras monitor New York City in real time.

Many of the community oversight laws are based on Community Control over Police Surveillance, or CCOPS, a legal model designed by the American Civil Liberties Union. Earlier this month, the concept got its biggest boost to date when San Francisco became the first jurisdiction in the country to bar law enforcement and other city departments from using facial recognition technology.

Local lawmakers around the country took notice, and they didn't miss the fact that the ordinance created a CCOPS process to monitor how police use all surveillance technology. They've been calling the ACLU to learn more, said Chad Marlow, senior advocacy and policy counsel at the civil liberties advocacy group.

"The number of calls from legislators around the country as a result of facial recognition ban and CCOPS has absolutely gone through the roof," Marlow said.

Community relations



Even police advocates say the development could foster trust between law enforcement and the communities they serve. That trust has frayed in some cities because police have been secretive about the investigative tools they use.

Jim Bueermann, former chief of police in the California city of Redlands and past president of the National Police Foundation, says a policy of transparency will make police departments more effective.

"There's huge value for policing," Bueermann said in an interview, "especially in enhancing the relationship police have with their communities."

In addition to facial recognition, the technology includes surveillance cameras; license plate readers, which scan oncoming traffic to create a record of who's passing through an area; and cell site simulators, which are often referred to by the Stingray brand name.

The data from all of these tools can be compiled, as it is in St. Louis, to give police an idea of who's in a specific area. The tools scoop up information on both suspects and innocent passersby alike.

Cell site simulators became the subject of controversy when reports revealed that cities had allowed police departments to purchase them in secret agreements. The agreements included a legal provision that required the departments not to disclose the use of the technology.

Bueermann, the former police chief, says those types of arrangements drive a wedge between police and the people, adding that he wouldn't have considered such a purchasing agreement as a police chief.

Legal scholars say the debate over facial recognition, a technology that privacy advocates say could create a perfect surveillance state, has raised the profile of these other technologies, all of which passively capture data about our lives.

Andrew Ferguson, a law professor at the University of the District of Columbia, says the concerns about facial recognition have "focused attention" on the issue. Ferguson, who studies the use of data to prevent crime, known as predictive policing, says the impact of the debate will be much broader than banning one form of surveillance technology in one city.

"The democratic oversight provision is just as significant as the facial recognition ban," Ferguson said. "It shows that the citizens will have some control over all of the different types of big data technologies."

A community oversight program in St. Louis would make a big difference, said Tatum, the activist.

Having more facts about police surveillance would help ease uncertainty about how the technology is actually used, she says. It would also let members of the community voice how they're affected by the technology, she said. The more the community can discuss surveillance technology, the more it will be aware of potential problems it can cause. And that can prompt meaningful dialogue.

"I don't think that's the kind of conversation people are having at the dinner table," Tatum said.