A man was arrested today on suspicion of murdering woman who died after being attacked.
The woman, 21, died in hospital in Nottingham yesterday after being found with serious injuries at a house in New Basford in the city yesterday morning.
Today Nottinghamshire Police said a 26-year-old man was detained after he voluntarily went to a police station at around noon.
They said a post mortem examination had been carried out, but details are not being disclosed.
The woman will be named after she has been formally identified, a spokesman said.
Earlier today police said they thought the woman knew her attacker.
Detective Chief Inspector Kate Meynell said: "I would like to reassure the public that we do not think this was a random attack and believe this young woman knew who assaulted her.
"It is still imperative that we speak with anyone who has information about the events which led to this death."
Officers went to the house in Springfield Street at about 7am yesterday after reports that a woman had been assaulted.
The woman, who is believed to have a young daughter, was found unconscious and taken to the Queen's Medical Centre, Nottingham, but pronounced dead a short time later.
Today the house remained cordoned off while forensic investigators examined it, as well as another house in Bulwell, Nottingham.
Several bunches of flowers and a candle were near the house today.
One read: "Words can't describe the pain. I will miss all the good times. The girls can't understand.
"No more pain, no more crying, rest in peace. Carla and girls."
Neighbours described the woman as quiet, and some described seeing her with a child.
Paul Jackin, 60, said: "All I know was I used to see her walking to and from the shop.
"She was a nice young lady, kept herself to herself."
Another neighbour, who did not wish to be named, said: "I only knew her to say hi to. She was quiet, minded her own business. I think she had a little girl."