Two young boys may have seen their mother being stabbed to death by their father in a row over cash, police fear.
Beauty therapist Janee Parsons, 31, was discovered fatally injured after neighbours heard screams and called 999.
Her husband, heating engineer Andrew, 38, was arrested on suspicion of murder at their family home.
Their two sons, aged five and eight, were taken away by police and will be cared for by the victim’s father and sister who are flying in from the US.
Shocked neighbours said the family were under financial pressure and had recently set up two businesses in a bid to raise money.
One said: ‘My children are friends with the kids and they feel like they want to help but they just can’t.’
The victim’s sister, Jocelyn Brady, said her family, who live in Yukon, Oklahoma, have been devastated by her death.
Boarding a plane to London, she said: ‘Everybody loved Janee. She was a very special person and very tenacious and she was my best friend.’
Police were called to the Parsons’ family home in Bicester, Oxfordshire, on Saturday at 10.30am after neighbours reported hearing a heated argument and screams.
Witnesses described half a dozen emergency services vehicles descending on the street. Paramedics discovered Mrs Parsons with fatal stab wounds, and despite desperate attempts to save her life she died at the scene.
Last night neighbours left floral tributes outside the £300,000 three-bed detached home that the family had been renting for 18 months.
One said: ‘To my wonderful friend Janee, you were taken away from us and you are now looking down on us. I will never understand why?’
Another added: ‘Your boys will grow up knowing you’ll be watching over them, guiding them in every way, every day.’
The couple are believed to have moved to Britain from the US after Mrs Parsons sold her health spa business in Oklahoma when it ran into financial difficulty.
Mr Parsons, who has also worked as a fencer and builder, graduated from Bicester Community College in 1990. His mother Jean lives a short distance away.
Companies House records show he set up a heat pumps firm in October and his wife set up a company, called Wink Ink Ltd, two months earlier.