The Independent Police Investigative Directorate (Ipid) has declined to comment on reports it has registered a criminal case against national police commissioner Gen Khehla Sitole.
According to media reports on Thursday, Ipid registered the case at the Pretoria central police station in December.
It wants Sitole investigated for his alleged failure to co-operate with Ipid's probe into the murder of Cape Town anti-gang unit detective Charl Kinnear.
Ipid head Jennifer Ntlatseng escalated the matter to police minister Bheki Cele on Wednesday.
Ntlatseng is reported to have informed Cele about the directorate’s frustration in its bid to get the police commissioner to co-operate.