The 85-year-old man who died of a stab wound at his home this morning has been named locally as Alan Grayson.
Police discovered Mr Grayson after being called to the address at 9.45am. He was treated for a stab wound at the scene but later died from his injuries.
An 83-year-old woman was arrested at the scene on suspicion of murder following the incident on Orgreave Lane in the Handsworth area of Sheffield, South Yorks.
A neighbour, who lives a few doors away from Alan, spoke of her "disbelief" at what had happened.
She told how Alan, who lived at the address with Marjorie Grayson, 83, were a "lovely couple" who she had known "all her life" and were "always together".
The woman, aged 57, who did not want to be named, told how Alan and Marjorie had lived in the semi-detached home in Handsworth since before she was born.
She said Alan was an architect or "used to do something do with drawing" while Marjorie worked at a local garage.
The neighbour revealed the couple had two sons and also grandchildren.
She said: "I'd been on an early shift this morning then came home and saw all this happening.
"At first, you just think someone's been taken ill when you see an ambulance.
"They were lovely - always just pottering around in their garden and always stopped for a proper chat.
"They were one of the originals from the street still left. It's just hard to believe - I'm so upset.
"Marjorie was good friends with my mum."
The woman said police had knocked on her door to ask what kind of relationship the elderly couple had and whether they had ever been seen arguing.
She said police had described it as a "tragic domestic incident."
The woman added: "They used to go out walking together all the time. That's why this is so hard to get your head around."
The woman's husband said: "I was amazed when I opened the curtains at 8.45am - I hadn't heard anything.
"Paramedics and police cars were there then more and more started showing up."
Another neighbour said: "It's somebody's elderly parents and grandparents - so God bless them as far as I'm concerned."