The so-called "Waterkloof Four" were released under strict parole conditions on Tuesday, correctional services said.
"They have been given strict parole conditions that include regular reporting to the Kgosi Mampuru Community Corrections Office in Pretoria," spokesperson Manelisi Wolela said in a statement.
The four were released after signing and receiving a brief orientation on their parole conditions in Pretoria.
Their sentences will expire in 2019, said Wolela.
Reinach Tiedt, Gert van Schalkwyk, Christoff Becker, and Frikkie du Preez were part of 64 offenders released on parole. The four were sentenced to 12 years each for murdering an unidentified man in a Pretoria park in 2001.
Last year, the high court in Pretoria ordered Tiedt and Van Schalkwyk back to Zonderwater Prison after they were released under correctional supervision.
A full bench of judges set aside district magistrate Peet Johnson's ruling of December 15 2011, to convert the men's prison term to correctional supervision. An application had been brought by the minister and the correctional services department commissioner to set aside Johnson's order. – Sapa