ian ▁aud ien ces ▁to ▁that ▁experienced ▁by ▁folk ▁pur ists ▁who ▁witness ed ▁Bob ▁D yl an ' s ▁early ▁" elect ric " ▁concert s ▁- ▁the ▁perform ers ▁sport ed ▁long ▁hair , ▁wore ▁out land ish ▁psych ed el ic ▁cost umes , ▁used ▁electric ▁gu it ars ▁and ▁ampl ification , ▁and ▁played ▁at ▁full ▁volume . ▁Brazil ' s ▁military ▁jun ta ▁was ▁becoming ▁increasing ly ▁susp icious ▁of ▁the ▁an arch ic ▁anti - est ab lish ment ▁att itudes ▁of ▁the ▁Trop ical istas , ▁who ▁also ▁found ▁themselves ▁at ▁odd s ▁with ▁the ▁national istic ▁student ▁left - wing , ▁who ▁fav oured ▁traditional ▁Brazil ian ▁musical ▁forms , ▁and ▁rejected ▁what ▁they ▁saw ▁as ▁the ▁cor rupt ing ▁influence ▁of ▁Western ▁pop ▁music . ▁ ▁In ▁September ▁ 1 9 6 8 ▁Ca et ano ▁Vel oso ▁gave ▁two ▁tum ult uous ▁performances ▁at ▁the ▁third ▁annual ▁International ▁Popular ▁Song ▁Festival ▁in ▁Rio , ▁where ▁the ▁audience ▁included ▁a ▁large ▁cont ing ent ▁of ▁left - wing ▁students ▁who ▁were ▁veh ement ly ▁opposed ▁to ▁the ▁Trop ical istas . ▁When ▁Vel oso ▁( back ed ▁by ▁Os ▁Mut antes ) ▁performed ▁in ▁the ▁first ▁round ▁of ▁the ▁Festival ' s ▁song ▁competition ▁ ▁on ▁ 1 2 ▁September , ▁he ▁was ▁initially ▁gre et ed ▁with ▁enthus i astic ▁app la use , ▁but ▁the ▁situation ▁soon ▁turned ▁ugly . ▁D ress ed ▁in ▁a ▁sh iny ▁green ▁pl astic ▁suit ,