He was banned during the military Argentine dictatorship, which started in 1976. This dictatorship left an estimated 30,000 (7,000 documented and identified by name &lt;https://web.archive.org/web/20170329045510/http://www.jus.gob.ar/derechoshumanos/areas-tematicas/ruvte.aspx&gt; ) missing persons including his sister, Maria Cristina. Heredia collaborates closely with organizations that denounce the crimes of the dictatorship, such as the "Mothers of the Plaza de Mayo" and the "Grandmothers of the Plaza de Mayo", and also with organizations of indigenous peoples.