Chilean activist Murielita Navarrete, who disappeared in 1974 and of whom the Pinochet government eradicated all records

This fits the description in the song and comes from a website about the singing of Peggy Seeger. So I guess this name is found too.

Mandela and Bobby Sands are too easy.

Eduardo C. Mondlane is a possible fit assuming just one more spelling error by Peggy Seeger.

Wolfgang