Cosatu welcomed on Monday the Johannesburg Labour Court's decision to rescind the lifting of former crime intelligence boss Richard Mdluli's suspension.
“The federation urges the SAPS (SA Police Service), Hawks and Public Protector to urgently investigate all the extremely serious allegations made against him,” Congress of SA Trade Unions spokesman Patrick Craven said in a statement.
The court overturned the lifting of Mdluli's suspension on Sunday after it was lifted by the same court on Friday.
“The SAPS has to be scrupulous in investigating, and where there is evidence, charging and bringing to justice, any of its members found to be involved in crime,” said Craven.
Cosatu wrote to the Public Protector asking her to investigate the allegations made against Mdluli, and Police Minister Nathi Mthethwa, following a City Press report on 15 April.
Last year, Mdluli faced fraud and corruption charges relating to the misuse of a secret crime intelligence fund to buy luxury vehicles, and to hire family members.
He also faced a murder charge for the death of his former lover's husband, Oupa Ramogibe. The charges led to his initial suspension.
This year, all the charges were withdrawn and Mdluli was reinstated.
This was widely criticised by, among others, the Democratic Alliance and lobby group Freedom Under Law.
Mthethwa later moved Mdluli to a different division, but acting national police commissioner Nhlanhla Mkhwanazi decided to suspend him again.