The family of an academic strangled and stabbed in her flat have spoken of their devastation at the loss of their "devoted" daughter.
Dr Barbara Johnston's parents Anthony, aged 80, and Valerie, aged 79, who live in Walsall, said their daughter, an Oxford-educated medical researcher, had dedicated her life to the battle against cot death and premature birth.
Police were yesterday scouring a house in Faringdon, Oxfordshire.
Dr Johnston, aged 55, whose full name is Barbara Madeline Waldron-Johnston, was found strangled and stabbed 49 times at her flat in Oxford's quiet northern suburbs on Thursday.
She had returned to the UK just four months ago after working for 23 years in New Zealand, where she described her life as "peaceful and safe".
Officers battered down the door of the medical researcher's one-bedroom flat just off Woodstock Road at 1am on Thursday after her parents raised the alarm.
The couple had been unable to contact her and grew concerned.
The flat sits just a short drive along Oxford's Woodstock Road from Somerville College where Dr Johnston is believed to have studied for a research degree in the 1970s. Fellow alumni include Baroness Thatcher.
The area of north Oxford where the killing happened is known for its academic links as well as providing a backdrop to the classic Inspector Morse mysteries.
Inside the property, which Dr Johnston owned, police found her
body riddled with a total of 49 stab wounds of varying depths and a sweater around her neck - thought to have been used to strangle her.
In a short statement Dr Johnston's parents and brother Patrick described her as "dearly beloved".
They said: "We are all devastated by her tragic and untimely death and ask that our privacy be respected at this terrible time.
"Barbara was a dedicated research scientist who strove to forward work in the field of cot death and premature babies.
"She was intelligent, lively and a devoted daughter and she will be greatly missed by us all."
Police have revealed that there were no signs of forced entry, leading detectives to believe she may have opened the door to her killer.
Officers arrested a 42-year-old man on Saturday on suspicion of murder and last night were given a further 24 hours to hold him for questioning.