miguel osvaldo etchecolatz (1 may 1929 – 2 july 2022) was a argentine police officer. he worked in the buenos aires provincial police during the first years of the military dictatorship of the 1970s. etchecolatz was involved in the national reorganization process ("el proceso"). he was first convicted in 1986 of crimes committed during this period. he was known for being part of mass murders during the dirty war.