In the autumn of 1871, Levski and Angel Kanchev published the "Instruction of the Workers for the Liberation of the Bulgarian People", a BRCC draft statute containing ideological, organisational and penal sections. It was sent out to the local committees and to the diasporic community for discussion. The political and organisational experience that Levski amassed is evident in his correspondence dating from 1871 to 1872; at the time, his views on the revolution had clearly matured. As IRO expanded, it coordinated its activities more with the Bucharest-based BRCC. On Levski's initiative, a general assembly was called between 29 April and 4 May 1872. At the assembly, the delegates approved a programme and a statute, elected Lyuben Karavelov as the organisation's leader and authorised Levski as the BRCC executive body's only legitimate representative in the Bulgarian lands. After attending the assembly, Levski returned to Bulgaria and reorganised IRO's internal structure in accordance with BRCC's recommendations. Thus, the Lovech Central Committee was reduced to a regular local committee, and the first region-wide revolutionary centres were founded. The lack of funds, however, precipitated the organisation into a crisis, and Levski's one-man judgements on important strategic and tactical matters were increasingly questioned. In that situation, Levski's assistant Dimitar Obshti robbed an Ottoman postal convoy in the Arabakonak pass on 22 September 1872, without approval from Levski or the leadership of the movement. While the robbery was successful and provided IRO with 125,000 groschen, Obshti and the other perpetrators were soon arrested. The preliminary investigation and trial revealed the revolutionary organisation's size and its close relations with BRCC. Obshti and other prisoners made a full confession and revealed Levski's leading role. Realising that he was in danger, Levski decided to flee to Romania, where he would meet Karavelov and discuss these events. First, however, he had to collect important documentation from the committee archive in Lovech, which would constitute important evidence if seized by the Ottomans. He stayed at the nearby village inn in Kakrina, where he was surprised and arrested on the morning of 27 December 1872. Starting with the writings of Lyuben Karavelov the most accepted version has been that a priest named Krastyo Nikiforov betrayed Levski to the police. This theory has been disputed by the researchers Ivan Panchovski and Vasil Boyanov for lack of evidence.