Two members of the so-called Waterkloof Four, Reinach Tiedt and Gert van Schalkwyk, have been readmitted to the Zonderwater Prison, the correctional services department confirmed on Monday.
"The two reported for re-admission today [Monday] at 12.30pm, they have now been readmitted," said the department's regional commissioner, Zacharia Modise.
Tiedt and Van Schalkwyk's recent application for leave to appeal against an earlier ruling that they return to the facility, was dismissed on Sept 16 by the High Court in Pretoria.
The two had been under house arrest for almost two years.
The two, along with Christoff Becker and Frikkie du Preez, were sentenced in January 2005 to 12 years' imprisonment for murdering a man in a Pretoria park in 2001.
They started serving their sentences in August 2008 after an unsuccessful appeal.
A Pretoria magistrate converted Tiedt and Van Schalkwyk's sentences to correctional supervision in December 2011 after an application by the Parole Board.
Correctional Services appealed against the decision and a full Bench of the High Court ruled in June that the magistrate's ruling had been based on an error in law and that the two must return to jail.
Judges Hans Fabricius, Ephraim Makgoba and Wendy Hughes found that the pair were not entitled to parole if more than five years of their sentence remained.
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