Darlington attack victim Sybil Sibthorpe died of head injuries
An 80-year-old grandmother found dead in her back yard was beaten to death, police said.
Sybil Sibthorpe's body was found in Haughton Road, Darlington, on Wednesday. She died of head injuries, Durham Police said.
Three men, aged 33, 40 and 44, were arrested at the scene on suspicion of her murder.
The mother-of-two's husband William, 77, said he could not understand why anyone would want to hurt her.
Forty officers are working on the case and an incident room had been set up in Bishop Auckland.
The three suspects, a 44-year-old man from Peterlee; a 40-year-old from Darlington and a 33-year-old Bishop Auckland man, are being quizzed at different police stations.
Mr Sibthorpe said: "Sybil was loved by all who knew her. We love her and that is tribute enough.
"She was a lovely, hard-working woman and why anyone should want to hurt her, I don't know."
Det Ch Insp Steve Chapman, of Durham Police, said: "We believe Mrs Sibthorpe was the victim of sustained attack and sadly died as a result of injuries suffered during that attack."