Harrison Kitt, who allegedly killed Greek Australian chief superintendent Ioanna Panayiotou (Joanne Shanahan), in a horrific high-speed crash at Urrbrae last April, pleaded not guilty due to mental incompetence.

The young man who also claimed the life of a suburban mother in a crash at Urrbrae said he was mentally incompetent due to a now-diagnosed illness.

The 55-year-old top-ranking police officer was involved in the three-car collision at the intersection of Cross Rd and Fullerton Rd in Urrbrae.

The 20-year-old driver who allegedly killed her and another woman pleaded not guilty to two aggravated counts of causing death, and one aggravated count of causing serious harm, by dangerous driving claiming he has been diagnosed with bipolar disorder and manic episodes.

His barrister, David Edwardson QC, told the Adelaide Magistrates Court that his client’s pleas were the result of extensive mental health analysis.

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Dr Paul Furst, Head of the state’s forensic community mental health service was one of the specialists also examined Kitt and issued a provisional report confirming the mental illness. That has been further confirmed by clinical psychiatrists at the Royal Adelaide Hospital.

Kitt is further accused of having caused serious harm to Superintendent Shanahan’s husband, Peter, who was driving their car at the time.

Court documents further allege Kitt’s offending was aggravated because he was speeding prior to the impact.

Chief superintendent Shanahan (nee Panayiotou), who has also served as acting assistant commissioner, was the passenger in a Holden SUV driven by her husband Peter Shanahan who sustained minor injuries.

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The other casualty, Tania McNeill aged 53 from St Peters, was the sole occupant of a silver BMW.

Magistrate Jayanthi McGrath remanded Kitt on continuing bail to face the District Court in January.