ST. PAUL, Minn. (AP) — George Floyd died because his breathing was restricted as he was restrained while handcuffed and facedown, a lung expert testified Monday at the federal trial of three former Minneapolis police officers charged with violating Floyd’s civil rights. Dr. David Systrom, a pulmonologist and critical care physician at Brigham and Women’s Hospital in Boston, said Floyd’s upper airway was compressed by Officer Derek Chauvin’s knee, while his position on the hard asphalt with his hands cuffed behind his back did not allow his lungs to expand, cutting off the flow of oxygen. “Oxygen delivered to the...