Federal prosecutors are investigating whether top Louisiana State Police brass obstructed justice to protect troopers who punched, dragged and stunned Black motorist Ronald Greene during his fatal 2019 arrest. It's a significant expansion of the federal inquiry that began as an examination of the troopers' violence against Greene. Investigators are now probing allegations top police supervisors disregarded body camera evidence, quashed a recommendation to arrest one of the troopers and pressed a state prosecutor not to bring any charges. That's according to documents obtained by The Associated Press and a half dozen people familiar with the case.