▁except ▁capt ains ▁and ▁ser ge ants , ▁who ▁must ▁spend ▁five ▁years ▁in ▁grade ▁before ▁becoming ▁el ig ible ▁for ▁promotion . ▁Classification ▁of ▁civ ili ans ▁was ▁based ▁on ▁a ▁non mil it ary ▁two - category ▁system ▁composed ▁of ▁super iors ▁( func ion arios ▁superior es ) ▁and ▁sub altern s ▁( func ion arios ▁sub altern os ). ▁ ▁In ▁the ▁mid - 1 9 8 0 s , ▁approximately ▁ 8 0 ▁percent ▁of ▁the ▁National ▁Police ▁Corps ▁were ▁uniform ed ▁car ab ine ers . ▁The ▁remaining ▁ 2 0 ▁percent ▁were ▁civil ian ▁police ▁investig ators ▁involved ▁in ▁crime ▁detection , ▁for ens ic ▁science , ▁administration , ▁or ▁log istics . ▁Appro xim ately ▁half ▁of ▁the ▁total ▁uniform ed ▁personnel ▁and ▁ 6 0 ▁percent ▁of ▁the ▁non uniform ed ▁personnel ▁of ▁the ▁police ▁force ▁were ▁station ed ▁in ▁La ▁Paz . ▁The ▁La ▁Paz ▁Department al ▁Police ▁also ▁had ▁an ▁Ex pl os ives ▁Brigade ▁( B rig ada ▁de ▁Ex pl os ivos ), ▁which ▁was ▁sub ordinate ▁to ▁the ▁Fire ▁Corps . ▁The ▁ 6 0 0 - member ▁Tra ffic ▁Police ▁admin ister ed ▁traffic ▁law . ▁Only ▁officers ▁of ▁this ▁force ▁normally ▁carried ▁side ar ms . ▁All ▁motor cycle ▁pat rol men ▁were ▁commission ed ▁officers . ▁The ▁Fem in ine ▁Police ▁Brigade ▁( B rig ada ▁Pol icial ▁F emen ina ) ▁served ▁in ▁an ▁auxili ary ▁or ▁support ▁capacity ▁to ▁the ▁oper ational ▁units .