By Sarah N. Lynch WASHINGTON (Reuters) – U.S. federal prosecutors warned on Tuesday there is still a chance they could bring additional criminal charges in their case against the Proud Boys over their roles in storming the U.S. Capitol last year, in a failed bid to block Congress from certifying President Joe Biden’s election victory. “We did indicate the possibility of a third” superseding indictment, prosecutor Luke Jones said during a virtual hearing in the U.S. District Court for the District of Columbia. “We obviously can’t speak for the grand jury or know exactly how things will transpire, but we...