The fatal police shooting of unarmed black teenager Michael Brown on Aug. 9 in Ferguson, Mo., has put a renewed focus on police interactions with African Americans. Three teenagers in Georgia have a response: An app they developed called "Five-O," which lets users report and rate individual interactions with police.

It's essentially a Yelp for police.

Ima Christina, 16, said she and her brother Caleb, 14, and sister Asha, 15, started work on the app at the beginning of the year. It grew from conversations initiated by their parents about police brutality and finding solutions.  The three are well-versed in computer science and design, having dabbled in side projects for some time. The two girls took a week-long course on app development at Georgia Tech, Ima said, while her brother Caleb has used MIT's Scratch programming.

“For us, we’re still trying to process it," Ima said of the Michael Brown shooting. "It’s kind of alarming the rate that’s going on... We have friends and family who are with the police, so we try and sympathize with that side. But we have family members who have had incidents with law enforcement and the police that have been not so positive, so we want to make sure we find a way to balance the two.”

Five-O, which is in beta testing and set to be released Monday for Apple and Android devices, isn't the first app that's intended to hold police accountable. The American Civil Liberties Union chapter in New Jersey released an app in 2012, for instance, that let people record police interactions, and provided legal information. Five-O also provides a "Know your rights" primer, using information from the ACLU.

People can provide detailed information on Five-O about an interaction with a police officer, including where it took place, as well as their own race and gender. It lets people around the country rate their local law enforcement, and includes message boards as well.

An app like Five-O underscores how trust of the police is not a given, particularly among African Americans; 70 percent of blacks said police treat them less fairly than whites, according to a 2013 Pew Research survey. And in a 2013 Gallup poll, nearly a quarter of black men between 18 and 34 said the police had mistreated them in just the previous 30 days.

Five-O also represents an interesting counter to SketchFactor, a crowd-sourcing app that lets people rate how "sketchy" a neighborhood in Washington is. One of the developers called it an "empowerment tool." The problem: "sketchiness" is subjective, and the app, developed by a pair of white millennials, has faced criticism that it encourages racial profiling and risks labeling entire communities as unsafe.

The developers of Five-O (and their company, Pinetart, Inc.), say they don't want to focus on just the bad. And Ima said she doesn't believe the crowdsourced nature of Five-O will encourage only negative reviews of the police. "We generally think people will be motivated on both sides, whether they have a good interaction, to chart that and put it into the system, or if they have a bad one," she said. "We want to make sure that people can detail their interactions whether they are positive or negative. The positive interactions should be a model for the negative interactions."