Victim's mother wants CCC input

Ingrid Bishop at the roadside tribute to her son Josh Warneke. Picture: Leon Mead.

The mother of a young man who died after being found with massive head injuries on the side of Old Broome Highway has raised concerns with the State corruption watchdog that police interviews with her son's killer were thrown out of court because investigating officers had shown a "blatant disregard" for procedure.

A murder charge against killer Gene Gibson was dropped and he pleaded guilty to the lesser charge of Josh Warneke's manslaughter after Supreme Court Justice Stephen Hall ruled this month that the interviews, which allegedly included admissions, could not be used in evidence at a scheduled trial.

Mr Warneke's mother, Ingrid Bishop, said she wanted to independently contribute to an internal police investigation into the conduct of the officers involved in the case and had met Corruption and Crime Commission staff this week.

Justice Hall found police involved in the two-year investigation into the 21-year-old's 2010 death had repeatedly ignored the law during unfair and unreasonable interviews with Gibson over two days in August 2012.

He ruled the interviews were not voluntary, involved "serious breaches" of the Criminal Investigation Act and had placed Gibson at serious disadvantage after officers failed to get an interpreter for the Kiwirrkurra man, who had only basic English.

Ms Bishop said she could not change what had happened and the impact of the "incompetence and blatant disregard for procedure and protocols".

"What I can do is strive to ensure no other family is subjected to what we are going through right now and unfortunately for the rest of our lives," Ms Bishop said.

"There are many unsolved murders in WA, take the Claremont serial killings, and maybe through the example of Joshua's case we can ensure those families still waiting can receive the outcome that they so rightly deserve."

Police Commissioner Karl O'Callaghan said two weeks ago there would be a full internal inquiry into the officers' conduct. A spokeswoman said the inquiry, which would include contact with Ms Bishop, would be overseen by the CCC.

'What I can do is strive to ensure no other family is subjected to what we are going through right now.'" *Ingrid Bishop *