8 6 , ▁thousands ▁of ▁members ▁of ▁the ▁UP ▁and ▁other ▁left ist ▁parties ▁were ▁murder ed ▁( est im ates ▁range ▁from ▁ 4 , 0 0 0 ▁to ▁ 6 , 0 0 0 ). ▁In ▁ 1 9 8 7 , ▁the ▁President ▁of ▁the ▁UP , ▁Ja ime ▁P ardo , ▁was ▁murder ed . ▁In ▁ 1 9 8 9 ▁a ▁single ▁large ▁land holder ▁had ▁over ▁ 4 0 0 ▁UP ▁members ▁murder ed . ▁Over ▁ 7 0 % ▁of ▁all ▁Colomb ian ▁president ial ▁candidates ▁in ▁ 1 9 9 0 — and ▁ 1 0 0 % ▁of ▁those ▁from ▁center - left ▁parties — w ere ▁assass in ated . ▁ ▁G avi ria ▁and ▁Sam per ▁presiden cies ▁( 1 9 9 0 – 1 9 9 8 ) ▁ ▁During ▁this ▁period , ▁the ▁Colomb ian ▁government ▁continued ▁its ▁negoti ations ▁with ▁the ▁F AR C – EP ▁and ▁other ▁armed ▁groups , ▁some ▁of ▁which ▁were ▁successful . ▁Some ▁of ▁the ▁groups ▁which ▁dem obil ized ▁at ▁this ▁time ▁include ▁the ▁E PL , ▁the ▁ER P , ▁the ▁Quint ín ▁L ame ▁Ar med ▁Mov ement , ▁and ▁the ▁M - 1 9 . ▁ ▁On ▁ 1 0 ▁August ▁ 1 9 9 0 , ▁senior ▁leader ▁Jacob o ▁Ar enas , ▁an ▁ide ological ▁leader ▁and ▁founder ▁of ▁F AR C – EP , ▁died ▁of ▁a ▁heart ▁attack ▁at ▁the ▁Casa ▁Ver de ▁comp ound ▁in