The Brief Polk County deputies shot and killed a former Uber driver Monday in Lakeland after authorities said he pulled a gun on them. A security expert is urging rideshare passengers to verify their drivers and trust their instincts before getting into a vehicle. A deadly deputy-involved shooting in Polk County is raising questions about rideshare background checks and passenger safety. Polk County shooting investigationWhat we know:Deputies with the Polk County Sheriff's Office shot and killed Larry Riles Monday morning after authorities said he pulled a gun on them. Uber background screeningWhat they're saying:Kolko said having a vehicle set up to look like an active rideshare can deceive someone looking for a ride.