MIAMI (AP) — 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 and ramp up expectations of U.S. military action in Cuba like the one carried out in January in Venezuela to bring President Nicolas Maduro to New York on drug trafficking charges.

Following Maduro’s ouster, the Trump administration quickly turned its attention to his ally Cuba and ordered an economic blockade that choked off fuel shipments to Cuba, leading to severe blackouts and food shortages.

The U.S. war in Iran appeared to have given Cuban leaders something of a reprieve from U.S. talk of regime change. As Trump seeks to wind down that conflict, speculation has been growing that he may soon turn his attention back to Cuba after pledging earlier this year a friendly takeover of the country if its leadership didn’t open up its economy to American investment.

Richard Feinberg, a professor emeritus specializing in Latin America at the University of California-San Diego, stated that while an indictment of Castro would resonate with voters in south Florida, it is unlikely to spur Pentagon planners to pursue a military campaign just 90 miles from Florida.

“There’s no easy Venezuela copy,” Feinberg noted, emphasizing the complexities in the situation.

Trump, when asked about the indictment on Air Force One, deferred to the Justice Department but described Cuba as a declining country in need of assistance, hinting at possible further actions.

Cuba's shootdown of the Brothers to the Rescue planes was a pivotal event in U.S.-Cuba relations, historically complicating engagement efforts from previous administrations. The potential indictment of Castro could impact ongoing diplomatic discussions and future relations.