Richard Carruthers, the designer who restyled the 2000 Sydney Olympic cauldron after the Games, has been murdered in his home in Sydney.

The Sydney Morning Herald, one of Australia's leading newspapers, reported Monday that the attacker's motive is a mystery.

Carruthers, 36, whose company was involved in the redesign of the cauldron, familiar to millions from the opening ceremony in 2000, when Cathy Freeman lit the Olympic flame.

The cauldron was recreated as a water feature and now stands outside the stadium.

The stabbing murder of Carruthers left detectives weighing two possibilities. He was either intentionally targeted by his killer for unknown reasons, or he was the random victim of a home invasion or burglary gone tragically wrong.

"We just don't have a motive at this stage," Acting Detective Inspector Kevin Fitzgerald of Castle Hill police was quoted as saying.

Carruthers's 27-year-old wife was injured in the attack, and was recovering Sunday night under police guard in an undisclosed hospital.

The couple were asleep in the master bedroom of their Spanish-style home in Castle Hill in Sydney's northwest.

Detectives said an intruder broke in early Sunday morning. The couple were woken, and the man set upon Carruthers in the bedroom in what police described as a vicious "aggravated assault."

His wife was also attacked, but managed to flee and ran to the street bleeding from what appeared to be slash wounds across her hands.

She screamed for help, and a neighbor ran into the street armed with a baseball bat but found no trace of the attacker.

Police believe the assailant entered and left the couple's property by climbing a brick fense in a street bordering their house.