Bolivia's Attorney General, Ramiro Guerrero confirmed that Deputy Interior Minister Rodolfo Illanesdied after being beaten numerous times by his kidnappers.
Authorities said more than 40 demonstrating miners have been arrested.
Five of those detained have been accused of direct involvement with the death of the 55-year-old minister. They include Carlos Mamani - the chairman of the national federation of mining cooperatives (Fencomin).
Illanes was kidnapped by striking miners during a visit to the town of Panduro, about 160 km (100 miles) outside of the capital of La Paz on Thursday. He had traveled to the area in order to initiate talks with miners at a roadblock.