▁one ▁of ▁BR CC ' s ▁safe ▁houses . ▁ ▁On ▁ 7 ▁June ▁ 1 8 7 1 ▁H rist o ▁" the ▁book b inder " ▁Ivan ov ▁invited ▁Nik ola ▁O bre ten ov ▁to ▁take ▁part ▁in ▁the ▁revolution ary ▁struggle ▁as ▁a ▁mess enger ▁between ▁Bulg aria ▁and ▁BR CK ▁in ▁Buch ar est . ▁On ▁ 2 9 ▁June ▁ 1 8 7 1 ▁O bre ten ov ▁travel led ▁to ▁Buch ar est ▁to ▁present ▁his ▁references ▁to ▁the ▁chairman ▁of ▁BR CK , ▁Ly uben ▁Kar avel ov . ▁After ▁being ▁approved ▁by ▁Kar avel ov , ▁Nik ola ▁O bre ten ov ▁along ▁with ▁Dim itar ▁Gor ov ▁of ▁Gi urg iu ▁developed ▁an ▁illegal ▁channel ▁for ▁transfer ring ▁mail , ▁printed ▁materials , ▁and ▁weapons ▁between ▁Buch ar est – Gi urg iu ▁and ▁R ous se . ▁ ▁Following ▁Ly uben ▁Kar avel ov ' s ▁and ▁Angel ▁Kan chev ' s ▁orders , ▁Nik ola ▁O bre ten ov , ▁T oma ▁K ard zh iev , ▁and ▁Rad i ▁Ivan ov ▁established ▁the ▁R ous se ▁private ▁revolution ary ▁committee . ▁The ▁constitu ent ▁session ▁of ▁the ▁committee ▁took ▁place ▁on ▁ 1 0 ▁December ▁ 1 8 7 1 ▁in ▁Nik ola ▁O bre ten ov ' s ▁( and ▁b aba ▁Ton ka ' s ) ▁house . ▁The ▁committee ▁later ▁admitted ▁Georg i ▁I k onom ov , ▁Gan cho ▁Kar am az hd rak ov ,