The Justice Department is preparing to seek an indictment against former Cuban President Raúl Castro, three people familiar with the matter told The Associated Press on Friday, as President Donald Trump threatens possible military action against the communist-run island. One of the people told the AP that the potential indictment is connected to Castro's alleged role in the 1996 shootdown of four planes operated by the Miami-based exile group Brothers to the Rescue. Castro was defense minister at the time. All three people spoke on the condition of anonymity because they weren't authorized to discuss an ongoing investigation. The Cuban government did not respond to a request for comment on the potential indictment, which was reported earlier by CBS. Any criminal charge against Castro, which would need to be approved by a grand jury, would dramatically escalate tensions with Havana. Following the U.S.…