A former major in the El Salvador army, after he left the military he co-founded the extreme-right-wing ARENA political party in El Salvador, and was long suspected of running death squads to assassinate political opponents and suspected guerrilla members, dating back to when he was in the army. In 1980 he and several civilians and soldiers were arrested by the Salvadoran government on a farm in the countryside on suspicion of organizing and committing the assassination of Archbishop Oscar Romero several weeks previously, and of plotting a coup d'etat against the existing Salvadoran government in order to install a military dictatorship. The charges were eventually dropped. In 2010 a former Salvadoran army captain who had admitted taking part in Romero's assassination confirmed that D'Aubuisson had personally given him the order to have Romero murdered.