They were on their way to meet with supporters of the Christian Liberation Movement, a Cuban dissident party Payá founded in 1988. Despite many threats, Payá continued his work.
For his work, the European Parliament awarded him the Sakharov Prize in 2003. Cepero was a fellow dissident and attorney from Ciego de Avila. Carromero was from Spain and Modig was from Sweden.
"My father dedicated his life so all Cubans could have rights," said Payá’s daughter, Rosa Maria Payá.
Carromero was driving when another vehicle rammed into the rental car from behind. He lost control and hit a tree. Payá died in the deserted road. Cepero died in a hospital in Bayamo. Modig said he was sleeping when the tragedy happened.
Rosa Maria Payá continues to demand an international investigation since her dad had dual citizenship from Spain and Cuba. She says the Cuban and Spanish governments continue to ignore her pleas.
Cuban authorities reported there wasn't evidence of another car and put the blame on Carromero. He faced vehicular homicide charges. After a trial and a coerced confession, he was sentenced to four years in prison. Cubans later released him to authorities in Spain.
Three years ago, Ortelio Abrahantes Bacallao, 42, a former officer with Cuba's Ministry of Interior, told El Nuevo Herald's Juan Tamayo government agents were to blame for the fatal crash.
Rosa Maria Payá met with Pope Francis in 2014. She has continued her father's work with the Cuba Decides campaign. She said the harassment of dissidents continues on the island. A group of dissidents recently marched to a Roman Catholic church.
"Some opposition members were not allowed to attend Mass," Payá said.
Local 10 News Andrea Torres contributed to this story from Miami.