Police investigating the murder of a woman who was stabbed to death in a Hull street have been given more time to question a man they are holding.
Tina Stevenson was a mother-of-five
Tina Stevenson, 31, was seven months pregnant with twins when she was killed in Wellsted Street on Wednesday.
Det Supt Ray Higgins of Humberside Police said she was the victim of a "shocking and appalling" attack.
Detectives have until the early hours of Friday to quiz the man, who was arrested on Wednesday night.
Ms Stevenson's twins also died in the attack, which happened as she was walking home from an ante-natal class.
Mr Higgins said efforts had been made to treat the baby boys after Mrs Stevenson died but nothing could be done.
He said: "Tragically, both babies lost their lives along with their mother.
"There was an attempt to assist the welfare of [them] but it was quickly realised they would be underdeveloped."
The arrested man is understood to have been involved in a relationship with her at some point.
None of Mrs Stevenson's children lived with her at her home in Gee Street.
Three of her children, two boys aged ten and nine and an eight-year-old girl, live elsewhere in Hull.
Two teenage daughters of Mrs Stevenson live elsewhere in the country.
She was not originally from Hull and police have not yet traced relatives in the city.
Members of her family have been traced in Fife, Scotland and in Derbyshire.
Mr Higgins said officers were having trouble building up a picture of her life but they understood she had been married in the past.
He described the incident as a "dreadful, shocking, and appalling attack on a pregnant female in broad daylight".
Mr Higgins said he could not rule out the possibility that it was a random attack, but added that he hoped it was a "one-off, isolated incident".