Chamorro is also a member of the ELN's Central Command (COCE). Erlinto is in charge of the group’s military strategy and arms procurement. He also manages the international relations team and the group's funds abroad. Erlinto joined the ELN around 1975 and rose through the ranks quickly. By 1980, he was part of the COCE. After longtime ELN leader Manuel Pérez, alias "El Cura," died, Erlinto became the military commander of the ELN. He is considered one of the group's hardliners and is responsible for trying to upgrade the ELN's military capabilities.
Despite his reputation, Erlinto has been tapped to be the ELN's official spokesman during several different peace negotiations between the group and the government. In February 1999, Erlinto and Víctor G. Ricardo, then Colombia’s High Commissioner for Peace, met in Caracas to discuss the final arrangements for the National Convention that was to be held that year in Colombia. The ELN requested the demilitarization of three municipalities for a “Meeting Zone” for a constitutional convention, but negotiations failed. In 2000, Erlinto met in Geneva with the government’s new peace commissioner, Camilo Gómez, but once again peace talks were suspended when Erlinto accused the government of supporting paramilitary groups.