Detectives are quizzing a man over the murder of an elderly charity fundraiser and the attempted murder of her councillor husband.
Freda Walker, 86, was viciously attacked in the neat semi-detached house she shared with ex-miner husband Ken, 88.
Ken, a former Labour councillor, remains gravely ill in hospital after being “left for dead” by the attacker.
Paramedics went to the couple’s house in Langwith Junction, Derbys, on Saturday morning after a neighbour raised the alarm.
They found Freda dead and Ken critically ill. Police said the elderly pair had suffered “horrific” injuries.
Derbyshire Police said they arrested a suspect, 33, overnight on suspicion of murder and attempted murder in Warsop.
He is being quizzed by detectives.
Police were probing if someone Freda befriended during her charity fundraising was responsible for the attack.
They were also looking into any links to a raid on the home of an elderly couple in neighbouring Nottinghamshire.
Freda was a keen fundraiser who was passionate about helping the homeless and those in need.
The devoted couple had been married for 64 years and had lived in the house since the 1960s.
A neighbour said: “Freda was the most generous person you could ever meet and had such a kind and warm spirit.
“The couple didn't have any children and I think helping others was her way of being a mother to those who were less fortunate.
“She worked with homeless charities and just wanted people to have a chance to make a life for themselves.
“The community is in real shock. It's so sad and an awful thing to happen to two pillars of their community.”
Ken is the ex-chairman of Bolsover District Council and friends with the former Labour MP Dennis Skinner.
He is also a governor at the local primary school and keen gardener who grew vegetables at a nearby allotment.
Before retiring he was a mining safety inspector and a former director of Derbyshire Miners Investments.
He celebrated his 88th birthday last Thursday, two days before he and his wife were brutally attacked.