Brother Murdock was sent to Ephebe by Vorbis to convert the locals to Om. A task which he completely failed to achieve. He spoke in the public forum and was shouted down, pelted with vegitables and stones. Though injured he returned to Omnia, where he died at the hands of the Quisition.
Vorbis knowing he would fail in this task set up plans for retribution before Murdock had even been sent to Ephebe and claimed that they had murdered him to justify the attacks.