The former chief of the feared spy agency responsible for kidnapping, torturing and killing thousands during Chile's military dictatorship has accumulated 500 years in prison sentences.

Eighty-six-year-old Gen. Manuel Contreras has been serving a combined sentence for crimes against humanity. On Wednesday, the Supreme Court sentenced him to 15 more years for the 1974 killing of Ana MarIa Puga and Alejandro de la Barra Villarroel.

Four former spy agency members were also sentenced for the killing of the couple.

After the 1973 military coup led by Gen. Augusto Pinochet, Contreras formed and commanded the DINA spy agency and became the most powerful and feared figure of the dictatorship after Pinochet.

According to an official report, 40,018 people were imprisoned, tortured or slain during the 1973-90 dictatorship.