A self proclaimed white supremacist has been accused of sending letters of a violent nature from his prison cell.
Philip Arps was jailed in June for distributing the objectionable live-streamed video of the 15 March mosque attacks.
Concerns over the letters were raised in the Christchurch High Court this morning where Arps' prison sentence was being appealed.
Crown prosecutor Shivani Dayal said the Crown had not obtained the letters but described them as being of a violent nature which could cause further damage by spreading a message of hate.
Justice Dunningham gave her until Monday evening to get hold of them and make submissions.
Arps' defence counsel, Anselm Williams, will then have until Wednesday to respond before a decision on Arps' prison sentence appeal was made.
Arps was sentenced to 21 months in prison.