Findon stabbing death: Reason why 91-year-old husband Frank Dimasi is alleged to have stabbed his wife of more than 50 years to death

An elderly great-grandfather is expected to be charged with murder after allegedly stabbing his wife to death, amid claims he was angry over the state of their marriage of more than 50 years.

Maria Dimasi, 85, was found dead at the couple's home in Findon in Adelaide's west late Saturday evening.

Police were called to the house following reports of an incident and found Ms Dimasi's body with multiple stab wounds.

It is understood Ms Dimasi had previously returned home from a community event.

Her husband Frank Dimasi, 91, who uses a walker and is believed to have a neurological disability, was arrested at home and taken to Queen Elizabeth Hospital under police guard for treatment of non-life-threatening self-inflicted injuries.

The great-grandfather is expected to be charged with murder on Monday.

Dimasi was described by shocked neighbors as a 'vulnerable' man suffering from what appeared to be early dementia and who was often seen walking from their house to the corner shop and back again.

Forensic officers searched the house for evidence on Sunday before a deep-cleaned van was called to the property.

Ms Dimasi's death prompted an outpouring of tributes from all who knew her.

Ms Dimasi, better known in Adelaide's Italian community as 'Nonna Maria', was a much-loved cook who always prepared meals for the vulnerable.

She volunteered in her grandson's kitchen, Nonna's Cucina, a community meal service that provides meals for people recovering from illness or medical treatment, the elderly and people with disabilities.

Ms. Dimasi was also considered the community's “matriarch,” known for sharing her Italian recipes and attending birthday parties for local children.

Neighbors said she was in 'good health' and was often seen walking around her street with her mobility scooter.

Mrs. Dimasi was also known to be incredibly proud of her family and always doted on her three children, grandchildren and great-grandchildren.

South Australian Prime Minister Peter Malinauskas paid tribute to Ms Dimasi and praised her volunteer work at Nonna Cucina.

“On a personal level, Maria Dimasi has made a very important contribution to our state, especially in the Italian community in the western suburbs,” Mr Malinauskas told reporters.

“Nonna's Cucina, which will be well known to many South Australians, has done a fantastic job delivering meals to vulnerable people, especially the elderly.

“This is a good person who lost his life under tragic circumstances.”

Federal Health Minister Mark Butler also praised Ms Dimasi for her commitment to giving back to the community.

“Maria lit up the kitchen at Nonna's Cucina,” Mr. Butler said.

“She was always extremely generous and made sure no one ever left her business hungry.

“Maria gave so much to her community and will be deeply missed by her loved ones and all who had the pleasure of meeting her.”

Longtime friend Frank Tripoli knew the couple for more than 50 years.

Mr Tripoli moved to Australia at the age of 11 and had fond memories of the Dimasi house in the 1970s.

“He was a good man, a very good man,” Tripoli said The advertiser. 'She was a lovely woman. I could not believe it.'

Another friend described the pair as “very good neighbors” and “a happy couple.”

Neighbor Dmytry Makukh said he was “really shocked” by the tragedy as Ms Dimasi was a “very helpful lady”.

I'm shocked, I'm really shocked. I can't believe this,” Mr Makukh said 9News.

'She was a very helpful lady and always cooked with my wife and gave her Italian dishes.'

The couple's home remains a crime scene as the investigation continues as police try to determine the exact circumstances.