Phil Walsh, the coach of the Australian Football League's Adelaide Crows, has been found stabbed to death at his home, South Australia Police say.
Officers had been called after a domestic dispute in the early hours of Friday. Mr Walsh, 55, was treated for knife injuries but died at the scene.
Mr Walsh's 26-year-old son has been arrested and charged with murder.
Mr Walsh's wife was taken to hospital after receiving non-life threatening injuries.
Police said that Mr Walsh had been stabbed multiple times and a knife was found at the scene.
"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," a South Australia detective told reporters.
Analysis: Wendy Frew, BBC Australia Editor, Sydney
Australia is known as a sports-loving nation but Australian Rules' fans love the game and their clubs like no other.
Aussie Rules, as it is known here, attracts bigger crowds than any other sport in the country, and it's got the nation's biggest stadium, the much-loved Melbourne Cricket Ground.
The state of Victoria is the heartland of a game where "big men fly", leaping in the air for the ball, sometimes climbing on the back of each other to do it.
South Australia - from where Phil Walsh hailed - loves the game too, with the Crows and Port Adelaide clubs dominating over the years.
Points are scored by kicking the ball between two tall goal posts.
It's something fans are proud of, dismissing Rugby League football, which dominates in the states of New South Wales and Queensland, as nothing more than "hand ball".
Police said the son, named as Cy Walsh by local media, had been living with his parents. He arrived home at about 02:00 local time (16:30 GMT on Thursday) and there was an argument.
Someone in the house called emergency services, who then called the police, said South Australian Police Superintendent Des Bray.
The son fled the incident but was found and detained for a psychiatric assessment. He is under police guard in hospital.
They are now gathering information from neighbours in Somerton Park, a seaside suburb of Adelaide.
Local media report that Adelaide Crows players have been gathering at the club's headquarters.
The team was scheduled to play Geelong on Sunday afternoon.
Phil Walsh's AFL career
The club said in a statement it was devastated by his sudden death.
"We ask if you could please respect the privacy of his family, as well as our players, coaches and staff, at this extremely difficult time," the club said.
It will hold a media conference, on Friday.
Mr Walsh was formerly an Australian Rules footballer, playing for several clubs before starting his coaching career.
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