Sandra Seagrave, 76, was named locally last night by witnesses who said she had been ‘beaten to death with her own walking stick’ while trying to intervene in the attack.
The other woman is understood to be 32. Both women died in the street on Hazel Way in Crawley Down, West Sussex, at around 10.20am on Sunday.
Witnesses said they heard a man shout ‘I’m going to kill you’ before Mrs Seagrave, known as Sandy, and the other victim, were both found dead on the street.
Police found a man, 37, badly injured inside a house on the road and arrested him on suspicion of murder.
He is now in a ‘very unstable condition’ under guard at Royal Sussex County Hospital in Brighton, police said.
The force also confirmed one of the victims was known to the suspect and added it was not a knife attack.
Mrs Seagrave’s heartbroken brother Dan Peckett, 84, told reporters outside her home yesterday: ‘I’m going to miss her so much. I adored her.
‘I kept in touch with her all the time on the phone.’
Mr Peckett, of the nearby village of Copthorne, added: ‘It’s a big shock at the moment.
‘I found out what happened on the telly. I haven’t been told anything yet.
‘The police have told me to go home and they’ll speak to me later.’
Mr Peckett’s son Michael, 60, said Mrs Seagrave tried to help a woman who was being attacked by a man.
Michael told MailOnline: ‘Her sister Maureen said she’d gone to help the lady who was getting a hiding and he attacked her as well.
‘We didn’t even know where she was attacked. She used a crutch or walking stick, but Maureen said she didn’t have the crutch that day.
‘I’m absolutely gutted. How do you put it into words? It’s just mad. She helped anybody that woman.’
He claimed the man used a knife to slash his own neck after the attack.
But Detective Chief Inspector Alex Geldart, of the Sussex and Surrey major crime team, has now stated that the incident was ‘not a knife crime’.
She added: ‘This is a tragic incident which has led to the death of two local women, one of whom was known to the suspect.
‘Members of the public, police and paramedics did all they could to help the victims but sadly the two women died at the scene.
‘I extend my heartfelt sympathies to their families, who are being supported by specialist trained officers.
‘I ask that people respect their privacy at this distressing time.’