The boy’s defence counsel Riaan Bode told Judge Frans Kgomo that they would continue to present evidence during the boy’s sentencing procedures this week.
Bode called Dr Eon Sonnekus, a juvenile criminologist, to the stand to testify.
Kgomo postponed the matter to Tuesday after the previous session in which the defence also presented the court with various evidence for mitigation in the court’s sentence.
The boy was earlier found guilty for the murders of Griekwastad farmer Deon Steenkamp, 44, his wife Christel, 43, and their daughter Marthella, 14.
They were shot dead on their farm Naauwhoek on April 6, 2012.
He was also found guilty on a charge of raping the girl and lying to the police.