The Trump administration amped up its aggressive posture against Cuba on Wednesday, announcing that the Department of Justice obtained a criminal indictment against former President Raúl Castro and several fighter pilots for shooting down a pair of American planes that were said to have entered the island’s airspace in 1996.

A Miami grand jury last month charged Castro, who is 94, and five others with murder, destruction of aircraft, and conspiracy to kill U.S. nationals for the deaths of four pilots who flew for the nonprofit Hermanos al Rescate, known as Brothers to the Rescue. The event 30 years ago marked a sharp decline in U.S.-Cuba relations and put a spotlight on a group of increasingly adventurous exiles who flew humanitarian missions to help Florida-bound refugees on rafts trying to make the 90-mile journey north.

“My message today is clear: The United States and President Trump does not and will not forget its citizens,” acting Attorney General Todd Blanche said at the public announcement.

The news was shared at a press conference in Miami’s Freedom Tower, a downtown building that was once considered the Ellis Island of the South. For 12 years, beginning in 1962, it housed the Cuban Assistance Center, which welcomed incoming migrants who were given preferential treatment and a pathway to U.S. citizenship after fleeing the Communist island.

“They were noncombatants, they were not armed, and they posed no threat,” said Southern District of Florida U.S. Attorney Jason Reding Quiñones. “For 30 years, the families have waited … today is a step toward accountability … the passage of time does not erase murder.”

These types of criminal charges are typically symbolic in nature, akin to the dozens of criminal indictments against Russian hackers and Chinese spies who are accused of breaking U.S. laws in the course of their foreign government work, but in reality face little to no time in prison without extraditions, which are unlikely. However, this indictment comes in the aftermath of a military-backed U.S. operation in January in which the leftist Venezuelan dictator Nicolás Maduro was abducted and whisked off to New York to face criminal charges in federal court. President Donald Trump had warned that “Cuba is next.”

Just hours earlier on Wednesday morning, Trump singled out Cuba when he delivered a speech at the Coast Guard Academy in Connecticut.

“From the shores of Havana to the banks of the Panama Canal, we will drive out the forces of lawlessness and crime and foreign encroachment just like we’ve been doing,” Trump said.

Any U.S. military incursion on the Caribbean island would be the most hostile action against the U.S. foe since the failed counterrevolutionary Bay of Pigs invasion in 1961, which involved anti-communist exiles trained and funded by the CIA.

Given that background, Florida Sen. Ashley Moody drew applause from the crowd when she read a penalty sheet that said Castro could spend life in prison. However, Blanche dodged reporters’ questions about whether the indictment could lead to military action.

In recent months, the United States has engaged in an unyielding military blockade that has cut off oil shipments to the island and devastated the population of 11 million, causing wide-scale disruptions in basic services and hospital shutdowns that have led to mass suffering. News of the Trump administration’s ongoing blockade has barely penetrated American news cycles.

Although government officials on Wednesday repeatedly referred to the downing of the humanitarian planes 30 years ago as “unprovoked,” the Brothers to the Rescue pilots had invaded Cuban airspace as part of its dissident efforts to drop anti-communist leaflets near the capital city of Havana. The Cuban government had officially complained to the U.S. government 24 times between 1994 and 1996 about American civilian planes violating Cuban airspace, but when those warnings went unheeded, the Cuban military prepared to take lethal action.

According to the unsealed indictment, Cuban spies had infiltrated the nonprofit to warn the communist government about its planned flights — information the Cuban government eventually used to coordinate the attack on Feb. 24, 1996, carried out by two pilots in a MiG fighter jet.

“At the time of their destruction, the two [Brothers to the Rescue] aircraft were flying outside of Cuban territory. In fact, they were flying over international waters, traveling away from Cuba. Despite their contact with the Havana air traffic control tower, the Cuban military did not provide BTTR with any warning of the imminent destruction of their aircraft,” the indictment says.

At the time, President Bill Clinton immediately denounced the attack and dispatched two F-16 fighter jets to guard search-and-rescue operations for the downed Cessna planes. The U.S. Coast Guard said it found only oil slicks some 15 to 18 miles north of Havana in international waters.

Court documents later revealed that the U.S. government had intercepted coded shortwave radio messages from Havana to its spies in South Florida communicating plans to shoot down the Brothers to the Rescue planes, but the FBI didn’t decrypt those messages until six months after the attack.

However, the indictment filed last month revealed new information that prosecutors say proves the culpability of Raúl Castro, who oversaw the military at the time and later spent a decade as president when his brother, Fidel Castro, fell ill. Raúl Castro, a mustachioed and bespectacled military officer nearly always seen in formal uniform, was less recognized internationally than his bearded and boisterous older brother, Fidel.

“All orders to kill by the Cuban military traveled through this chain of command with Castro Ruz and Fidel Castro as the final decision makers,” the indictment says.

Before Wednesday, the most significant U.S. response to the attack came in the form of immediate $300,000 payments to the families of the four pilots who had been killed, using funds the government had seized from Cuban assets held in American banks decades earlier.

Brothers to the Rescue played a pivotal role in providing safety to Cuban migrants who braved the shark-infested Caribbean waters in rafts to seek sanctuary in South Florida, where they were granted a direct path to citizenship as long as they could reach U.S. soil.

President Barack Obama ended the so-called “wet foot, dry foot” policy in his final days in office. The second Trump administration has aggressively sought to deport recent Cuban arrivals — sending them to sprawling detention camps like the Florida swamp tent jail dubbed “Alligator Alcatraz.”