Police say they are treating the death of a 25-year-old woman as murder.
Officers were called to a house in Lothian Road, Middlesbrough, shortly before 0900 BST on Tuesday following reports of a fight and screaming.
They found Nusrat Ali with multiple stab wounds in the garden. A man, who had been living next door, was found unconscious in the house.
Ms Ali died in hospital. Police say they are not looking for anyone else in connection with the incident.
Ms Ali was taken to James Cook University Hospital where, despite emergency surgery, she died shortly before midday.
The man, who is also believed to be in his 20s, is currently in intensive care in hospital.
Det Insp Stan Drummond said: "This incident happened as she was leaving home to go to work at a local call centre.
"It was witnessed by two builders who intervened to stop the assault. It was only then they realised she had been stabbed.
"We need to speak to anyone who knew Ms Ali or the man living next door to her family."