Polish police are hoping that smartphones will help them nab criminals.
The police are loading photos of wanted criminals on a phone app that combines real-life crime-stopping with an interactive game in which users try to match the suspects' faces with the charges against them.
The idea is that people who encounter a suspect on the street will use the app to send a message to police reporting their discoveries.
Piotr Bieniak, the officer in charge of the project, said police rely on citizens' help for one in every five arrests. He said authorities hope they can use popular new-technology techniques to expose criminals and bring them in.
Polish police say they have 36,000 people on their "wanted" list.
The new app will be available for both Apple and Android devices.