This study explored the effects of technological support on citizen searches during missing persons cases. A qualitative experimental design was used to investigate the effects of the prototype of an app, Sarea, developed by the Dutch police to help citizens initiate and coordinate a search. Two conditions were used: intervention groups, who were given phones with the app installed, and control groups without this support. A total of seven searches were conducted—four intervention groups and three control groups with group sizes between three and five people (N = 33). Data were collected through the System Usability Scale and one-to-one observation of individual searchers. The results showed that technology provides valuable support to citizens in coordinating and visualizing a citizen search. However, divided attention due to increased cognitive load during the search, and the unwarranted legitimization of human choices by a technological interface, can make collaboration between humans and technology problematic.