Location data gleaned from thousands of videos posted on the social network Parler and extracted in the days before Amazon restricted access to app this week, reveal its users included police officers around the U.S. and service members stationed on bases at home and abroad.

The presence on Parler of active military and police raises concerns, experts said, about their potential exposure to far-right conspiracy theories and extremist ideologies enabled by the platform’s practically nonexistent moderation and its stated openness to hate speech. Military officials have long considered infiltration and recruitment by white supremacist groups a threat. Groups that endorsed a wide range of racist beliefs appear to have been operating openly on Parler, the experts said, with the de facto permission of its owners. The FBI has likewise raised concerns over law enforcement agents adopting radical views and being recruited—viewing their access to secured buildings, elected officials, and other VIPs as a singular threat.

Location data gleaned from thousands of videos […]