They're warning more police officers, magistrates and judges could lose their lives if more is not done to protect them.

Police Minister Bheki Cele has promised a breakthrough in the Kinnear case within 72 hours.

Kinnear was shot dead in front of his Bishop Lavis home on Friday afternoon.

Former WC police commissioner Lennit Max said the police are not protected and can't protect themselves.

"Are you surprised that so many gang-related cases are unresolved? Because witnesses fear for their lives and they know the police can't protect them as well," Max said.

Former SARS crime buster Johann van Loggerenberg said deliberate attempts to scupper investigations from within are well documented.

"What we ought to be discussing, is what are the institutions doing to protect and ensure the safety of those individuals involved in high-risk investigations on behalf of the state," Van Loggerenberg said.

Max and Van Loggerenberg say factionalism within the criminal justice system has been threatening investigations for years.

Van Loggerenberg warns it's only a matter of time before more investigators come under attack.

eNCA