The Aussie rules coach was found fatally wounded with multiple knife wounds when emergency services were called to a domestic dispute at his home in the Somerton Park suburb of Adelaide. Ambulance crews made desperate attempt to save him but he died at the scene. His wife, Meredith, was taken to hospital with non-life threatening injuries.

Cy Walsh, 26, is understood to have been arrested nearby a short time later. He was detained for a psychiatric assessment at Flinders Medical Centre, and in a bedside hearing late on Friday he was remanded in custody until September 15.

Cy Walsh lived with the family, and the emergency call for an ambulance came from within the house at just after 2am. Ambulance officers then contacted police.

“There’s been an argument. I can’t tell you anything about the argument, but as a result of that both Mr Walsh and his wife received a wound, and the wound ultimately caused Mr Walsh’s death,” said one unnamed South Australia Police detective, quoted by the BBC.

Walsh had led the Crows to a 7-5 record this season after making the switch from crosstown rival Port Adelaide, where he served as an assistant in 2014. He had been involved in the game as player and coach for 33 years, and played 122 games in the AFL for Collingwood, Richmond and Brisbane, mostly as a wingman.

AFL chief executive Gillon McLachlan said the game was “in mourning”, and confirmed that the Crows’ scheduled match against the Geelong Cats on Sunday would not go ahead. He described Walsh as a man of “boundless energy and enthusiasm”.

Veteran Adelaide AFL journalist Michelangelo Rucci told 5AA: “I’m speechless, bewildered…a person that so many of us knew so well – I just can’t understand how this can happen. People who knew Phil Walsh will be waking up today in just absolute disbelief, just staggered that has happened. This is an extraordinary bit of news.”