Police said Ms Treloar was abducted from her home in Brownlow Road, Hackney, east London, at around 7:10 yesterday.
The 20-year-old was discovered with stab wounds in a grey Fiat Stilo in Ryder Mews, Hackney, at around 8:30am.
A Scotland Yard spokesman said: “Whilst we await formal identification we believe the victim to be Kirsty Treloar.”
Police and London Ambulance Service were called to reports of a disturbance.
The young woman was reported to have been abducted by a suspect who fled in a grey Fiat Stilo, Scotland Yard said.
At around 8:30am, police and ambulance crews received calls to Ryder Mews where a grey Fiat Stilo had been found abandoned with the injured woman inside.
She was pronounced dead at 8:34am, a police spokesman said.
A 22-year-old man and a 24-year-old woman were taken from the house in Brownlow Road to an east London hospital after suffering stab wounds.
The man is said to be in a stable condition and the woman was treated for a minor injury.
A month-old baby girl was also taken from the address to hospital as a precaution and remained there last night under observation.
A post-mortem examination for Ms Treloar will take place in due course.