Villalobos aiva mumwe wevatungamiri vakuru vePeople's Revolutionary Army, kana kuti "Ejército Revolucionario del Pueblo", boka rakabuda muEl Salvador mukutanga kwema1970 semubatanidzwa wemasero ane midzi mumapoka akasiyana-siyana echiMarxist uye ekuruboshwe echiKaturike. ERP yaiva imwe yemasangano mashanu akabatana pamwe chete muna 1980 kuti aumbe Farabundo Martí National Liberation Front munguva yeHondo yeVanhu veSalvador
, umo mauto akarwira kurudyi akarwa nehurumende yaEl Salvador yaitsigirwa nemauto uye yaitsigirwa neUnited States. Mudzidzi wezvehupfumi uye mushandi wekuruboshwe, Villalobos akabatana neERP muna 1971, pazera remakore 19. Kubvira ipapo akapomerwa mhosva yokubatanidzwa mukuuraya muna 1975 kwaRoque Dalton, mudetembi wechimurenga uye mumwe mutungamiri weERP uyo akapfurwa nehama dzake pashure pokunge kurwisana kwesimba muboka kwaita kuti apomerwe kuti aiva musori weCIA. Panguva iyoyo, kuuraya kwacho kwakatungamira pakuparadzana uye kupomerana mhosva mukati meERP uye kushoropodzwa kubva kune vamwe vekuruboshwe, asi mushure ma1980 Villalobos akasimuka kuti ave mumwe wevarongi vakuru vehondo veFMLN. ERP pasi pehutungamiri hwake yakatsanangurwa se "sangano remauto rinobudirira zvikuru kuruboshwe rweSalvador" munguva yehondo yevagari vemo, naVillalobos vachikudziridza "mukurumbira wekuchenjera kwakanaka". The Financial Times yakatsanangura Villalobos se"Tenzi wechokwadi wehondo yechikwata chemauto cheLatin America yomuzana ramakore rechi 20", ari pamusoro paChe Guevara.