Deon Steenkamp, his wife Christel and their 14-year-old daughter Marthella were murdered on their Naauwhoek farm near Griquatown. Photo: Supplied

Kimberley - The Griquatown farm murderer seems to be made of good human material, the Northern Cape High Court heard on Tuesday.

“The accused showed an overall good character and positive attributes for some 15 years and eight months before the crime,” Dr Eon Sonnekus, a juvenile criminologist, said in mitigation of sentencing.

“The accused still seems to be made of good human material.”

Northern Cape Judge President Frans Kgomo was listening to sentencing procedures for the 17-year-old boy convicted of three murders and rape.

Riaan Bode, for the teenager, called Sonnekus as the first witness for the defence during arguments in mitigation.

On March 27 the court found the boy guilty of the murders of Griquatown 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.

The boy was also found guilty of raping the girl and lying to police.

Sonnekus testified he could not explain the boy's criminal behaviour because he had not testified in his defence.

“The criminal behaviour is not in line with the overall social behaviour patterns the accused followed.”

Sonnekus told the court the boy's behaviour in his school life, sport activities and with his guardian family after the crimes were more in accordance with his social behaviour pattern.

He told Kgomo the boy could be rehabilitated.

During cross-examination Sonnekus said it was regrettable that the accused had not taken responsibility for the crimes.

Prosecutor Hannes Cloete asked Sonnekus if he agreed that the wounds on the three victims showed signs of “over-kill”. Sonnekus agreed.

He told the court some aspects of the case, such as the assault on Deon, would remain a mystery.

“When you testify that there are some aspects you could not explain, it becomes a problem for all of us.”

Cloete asked Sonnekus what guarantee people had that such anger would not surface again.

“What guarantee is there for other people in his presence?”

Sonnekus said there was none, even after long-term imprisonment.

“I do have confidence in the processes of correctional services. By the time he would get out, even on parole, there must be signs of remorse, an apology and taking responsibility.”

This, however, could not be guaranteed.

Sonnekus further agreed with Cloete that the matter existed in a vacuum because the boy had not given his side of the story.

“We can only blame the accused for this. In this case,” said Cloete.

Sonnekus agreed, saying: “In this case”.

The trial continues.