The 17-year-old boy has been convicted of killing a couple and their teenage daughter on their farm near Griekwastad, in the Northern Cape.
All the court knows about a 17-year-old boy who killed the Steenkamp family is that he is a murderer, Northern Cape prosecutor Hannes Cloete said.
"We have arrived at a time where his rights must be curbed," Cloete submitted to the court.
Northern Cape Judge President Frans Kgomo was hearing argument in an application for an extension of the boy's bail until sentencing at the time.
Earlier, Kgomo indicated that he did not really know the boy beyond the evidence that was before the court.
Cloete replied that it was now known that the boy was a cold-blooded murderer who wiped out a family.
He agreed that if the court looked at the reasons why the murders were committed, it did not paint a good picture.
"It would not be in the interest of justice that he gets bail again," submitted Cloete.
The boy's defence team suggested that strict bail conditions would be acceptable.
The boy's guardian testified in support, but the court was shown a picture where the boy had access to a firearm during a hunting excursion on the guardian's farm.
Kgomo replied that this fact made him feel creepy.
He refused bail and ordered that the boy be held at the Kimberley prison until the next hearing for sentencing procedures on May 13.
Earlier in the day, Kgoma convicted the boy on three counts of murder.
Kgomo also found the boy guilty on a rape charge and a charge of defeating the ends of justice.
"I am satisfied that the minor accused committed all the offences."
Kgomo said that the State had proved the charges beyond reasonable doubt.
"The murders were premeditated."
Northern Cape farmer Deon Steenkamp, 44, his wife Christelle, 43, and daughter Marthella, 14, were shot on their farm Naauwhoek, near Griekwastad, on April 6, 2012.
Kgomo held that the teenager also raped the girl and lied to the police.
The judge said that the girl was tortured before her parents were killed execution style.
Kgomo said he wanted to refrain from saying anything of the boy's demeanour in the witness stand, but remarked that the boy did not show any emotion.
He testified with a strong voice and did not even become flustered when the State painted him into an corner, the judge said.
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