Finn murder may not be solved: WA top cop

A 2002 royal commission was the golden opportunity to solve the Shirley Finn murder case, and a fresh probe may not reveal her killers, WA's top cop says.

WA Police Commissioner Karl O'Callaghan says the 1975 murder of a brothel madam may never be solved.

WEST Australian Police Commissioner Karl O'Callaghan says the 1975 gangland-style murder of brothel madam Shirley Finn will be a difficult if not impossible crime to solve.

MS Finn was wearing a ball gown and sitting in her parked car near the freeway in South Perth when she was shot four times in the head at close range.