Follow CBSMIAMI.COM: Facebook | Twitter

MIAMI (CBSMiami) – Tributes and vigils will be held Wednesday to mark the 20th anniversary of the downing of two Brothers to the Rescue planes.

Armando Alejandre Jr., Carlos Costa, Mario de la Pena and Pablo Morales were on a humanitarian mission when they were shot down by Cuban fighter jets. A third plane, with group founder Jose Basulto and Sylvia Iriondo, escaped.

Then-General Raul Castro gave the orders for Cuban military jets to shoot down the civilian planes over international waters.

“One of the most chilling things I have ever heard in my life is the audio recording of the regime pilots begging for orders to kill these men and then celebrating their takedown,” said Senator Marco Rubio in a statement. “The murder of these Americans was a gross violation of U.S. law for which justice has not been served. It also stresses the long history of brutality by the Castro regime.”

During the mid-90s, Brothers to the Rescue scoured the Florida Straits from small airplanes looking for Cubans who were trying to make their way to the U.S. on rafts or boats. Once spotted, they would drop relief supplies to them and then radio the Coast Guard their position so they could be picked up.

The group was also known to drop leaflets opposing the Cuban government over Havana.

Cuba considered the Brothers group provocateurs.

While the pilots of the two Cuban MIGSs and a military commander were indicted in the United States, none has ever been brought to trial.

“We must remember that 20 years later this crime remains unpunished,” said Iriondo, of Mothers Against Oppression.

Indeed, three spies in a network that helped plot the shoot down, and were convicted by a federal jury, were returned to Cuba in a swap for American businessman Alan Gross.

“They were condemned by the justice system and the justice system was condemned by this President Obama,” Basulto said.

There was condemnation of President Obama’s upcoming visit to Cuba and his his normalization of relations with the regime that continues to commit “human rights violations and atrocities.”

“It hurts,” Iriondo said. “It is very painful.”

Representative Ileana Ros-Lehtinen put out a statement criticizing the Obama administration for the concessions they’ve granted Cuba and chastised them for not pursuing prosecution those responsible for the downing of the planes.

“The Obama administration continues to provide the Castro regime – the same people who murdered the Brothers to the Rescue heroes – concession after concession without even a semblance of contrition or accountability by the murderers of these brave men. In fact, this administration returned convicted murderer Gerardo Hernandez and other members of the regime spy network back into Castro’s arms. President Obama has also not insisted on the extradition of those who committed these murders nor has he secured the return of several fugitives from American justice. The memories of the courageous Brothers to the Rescue heroes will endure as a testament to those who were willing to sacrifice everything for the cause of a free Cuba.”

A special tribute to the four men who died will was held Wednesday morning at the Brothers to the Rescue Monument at Opa-locka International Airport.

“These boys were believers in democracy, believers in free-trade, believers in all things that make this country great,” said Basulto.

At 3 p.m. the families of the men who died, along with friends and supporters, will hold a vigil at Florida International University’s Graham Center Fountain.

At 8 p.m. a Mass will be celebrated in the names at the Shrine of our Lady of Charity, La Ermita de la Caridad at 3609 South Miami Avenue.