Five times a day, tens of millions of phones buzz with notifications from an app called Muslim Pro, reminding users it’s time to pray... These features make it easier to practice the many daily rituals prescribed in Islam, turning Muslim Pro into the most popular Muslim app in the world, according to the app’s maker, Singapore-based BitsMedia. But revelations about the app’s data collection and sales practices have left some users wondering if the convenience is worth the risk.

BitsMedia sells user location data to a broker called X Mode, which in turn sells that information to contractors... Mass calls to delete Muslim Pro and a separate Muslim matrimony app called Muslim Mingle have since echoed across social media, resonating among communities that have long been the target of government surveillance.

... The Council on American-Islamic Relations, the nation’s largest Muslim civil liberties and advocacy group, sent letters to three U.S. House committee chairs asking them to investigate the U.S. military’s purchase of location and movement data of users of Muslim-oriented apps. CAIR called for legislation prohibiting government agencies from purchasing user data that would otherwise require a warrant.

In a statement, Muslim Pro denied that it sold user data directly to the U.S. military but confirmed that it had worked with X Mode... X Mode did not respond to requests for comment, but reportedly ceased working with two specific defense contractors...