The best witness the U.S. government may have to indict Raúl Castro in the 1996 Brothers to the Rescue shoot-down could be sitting in a federal prison, said a source who asked not to be named because of direct knowledge of the ongoing probe.

Gerardo Hernández, a convicted Cuban spy facing a life sentence if his appeals fail, managed the Red Avispa, a spy ring with at least 16 members broken up by federal authorities in 2001. He could have information that ties other Cuban government officials to the Brothers shoot-down, possibly even Raúl Castro, authorities confirmed.

''That's ridiculous,'' said Hernández's lawyer, Paul McKenna, who acknowledged Wednesday that the federal government has tried to get his client to turn state's evidence against Cuba.

Friday marks the 10-year anniversary of the attack, when Cuban MiGs shot down two unarmed civilian airplanes over international waters, killing three American citizens -- Carlos Costa, 29; Armando Alejandre, Jr., 45; Mario de la Peña, 24 -- and U.S. resident Pablo Morales, 29.

WANTED: RAUL CASTRO?

The victims' families believe Raúl Castro is the highest official in Cuba's chain of command who can be indicted under U.S. law for his alleged role in the shoot-down, as head of the Cuban armed forces.

An indictment may seem like a fool's errand to some people, but there is legal precedent, and family members say there are geopolitical ramifications to their quest for justice.

The legitimacy of Raúl Castro, who is next in line to succeed Fidel Castro as Cuba's leader, would be questioned in the international arena if he is under indictment by the United States, the families believe.

Interim U.S. Attorney R. Alexander Acosta said the case remains open but would not elaborate. "This is an active case in active litigation.''

But other U.S. officials who have been at the forefront of the case say anything is possible -- if the evidence supports it.

''You don't have to be an expert to know how that country is run, and who has the ultimate say and makes the decisions that would affect the country in such an immediate way,'' said Guy Lewis, a former U.S. attorney for the Southern District of Florida who oversaw the prosecution of the Avispa trial. ``I think they [the MiG pilots] were following orders from their superiors . . . Without speaking to any individual or potential defendants, like Raúl Castro, it was clear in my mind that the evidence supported the fact that these individuals did not act alone.''

SPY WOULD NOT FLIP

Hernández could provide the key for indicting high-level Cuban government officials. Hernández was sentenced for his role in the Brothers attack, as well as for an espionage plot targeting military bases and exile groups.

The source said that federal authorities tried to get Hernández to testify against his superiors back in 2001, but he wouldn't do it.

''But if this guy's sentence gets affirmed and he is facing life in prison, and his appeals have been exhausted, maybe he'll have second thoughts,'' the source said.

McKenna said the government has tried to flip Hernández multiple times.

''He [Hernández] has been approached in every conceivable manner to cooperate with the government and his position has always been, `I didn't know what they [the Cuban military] were going to do,''' McKenna said. ``His job was to monitor Brothers to the Rescue to find out when they were going to fly and pass that along, but he never knew what they were going to do. He never had any indication that they were going to shoot them down.''

Many exiles also blame Fidel Castro, but the victims' family members and federal authorities concede that under international law, indicting a head of state is much more difficult.

Wayne Smith, former chief of the U.S. Interest Section in Cuba and an opponent of the U.S. embargo OF Cuba, scoffs at the notion of indicting either Raúl or Fidel Castro.

''It's absolutely stupid,'' said Smith, who added that Cuba's attack on the planes was wrong.

``That's something only the absurd right wing in the Cuban-American community can come up with, and it would not stand up in any court outside Miami.''

EXISTING PRECEDENTS

There have been other indictments over the years.

In 2003, the U.S. government indicted Cuban Air Force Gen. Rubén Martínez Puente and two MiG fighter pilots, brothers Lorenzo Pérez Pérez and Francisco Pérez Pérez, for their roles in the shoot down. It was a largely symbolic gesture because there is no extradition agreement between Cuba and the United States.

Marcos Jimenez, who was U.S. attorney when those Cubans were charged, said indicting a high government official from another country requires Justice Department approval.

''A local U.S. attorney is not going to act independently,'' Jimenez said.

Justice Department spokesman Drew Wade said, ``We never confirm or deny the existence of criminal investigations.''

It isn't the first time the U.S. government has considered indicting Raúl Castro, however.

Back in 1993, U.S. prosecutors drafted an indictment against Raúl Castro, alleging that he led the Cuban government in a 10-year racketeering conspiracy to import cocaine from Colombia's Medellin cartel through Cuba and Nicaragua into the United States. It was never pursued.

Perhaps the most high-profile indictment of a foreign head of state by the U.S. attorney's office in Miami is former Panamanian leader Manuel Noriega.

The families of the shoot-down victims have never stopped lobbying the government for more indictments.

''The indictment of all Cuban government officials criminally responsible will not only serve to vindicate the families and this community . . . but it will also serve to ensure the future of freedom and democracy in Cuba,'' three family members -- Mirta Costa, Miriam de la Peña and Maggie Khuly Alejandre -- said in a June 6 letter to Secretary of State Condoleezza Rice.

José Basulto, the founder of Brothers to the Rescue and the only pilot who got away from Cuban MiGs that day, believes there is blame on both sides of the Florida Straits. He thinks that Washington could have done much more to prevent the shoot-down, but did not act, keeping fighter jets grounded at Homestead Air Reserve Base. Like the families of the victims, Basulto filed a multimillion dollar lawsuit against Cuba recently and won. But he has not yet collected the $1.75 million he was awarded, he said.

''The will to act is the only thing that is missing to indict Raul and Fidel,'' Basulto said. ``The reason they haven't done it is because of involvement from the White House.''

Copyright Miami Herald 2006