A man suffering dementia who killed his 75-year-old wife at their Piara Waters home on March 20 was unlikely to stand trial.
Eighty-seven-year-old John Huggins was accused of stabbing his wife to death.
Emergency services were called to the Guerin Avenue address and police said upon arrival they found the woman with critical injuries.
She died a short time later at the scene.
At the Supreme Court last week Mr Huggins was granted bail on condition he be kept in a special ward at Armadale Hospital and not be allowed to leave without doctor authorisation.
Justice Lindy Jenkins said it was likely Mr Huggins would be declared unfit to stand trial because of his illness.