In 1980 El Salvadoran Archbishop Oscar Romero spoke out against the repression of the Salvadorean people. One day later, he was murdered by a right-wing death squad for 
speaking truth to power. Below is a link to a video about Romero as well as a clip from the film “Romero”, which contains the speech that got him killed:
The Murder of Monsenor, Part One
The Murder of Monsenor, Part Two