Authorities in Cuba say driver error was to blame for the car accident in which prominent activist Oswaldo Paya died.
The Interior Ministry said Friday the driver, Angel Carromero of Spain, was speeding when the car hit an unpaved stretch of road and spun out of control.
It said the vehicle hit a tree, killing Paya and another Cuban activist on Sunday.
On Paya's Web site, his daughter, Rosa Maria, posted an audio clip saying Pay’s family believed a second car was involved and that it had intentionally struck the car in which Paya was traveling.
Paya, a devout Catholic, gained international fame as the top organizer of the Varela Project, a petition campaign for reforms to Cuba's one-party state.
In 2002, Paya received the European Union's top human rights award, the Sakharov Prize, named after the late Soviet dissident Andrei Sakharov.
Paya is the second key Cuban activist to die within the year. Laura Pollan, the founder of the protest group, Ladies in White, died in October.