Police are appealing for the driver of a red car to come forward after two young girls were were killed last Thursday evening on the A47 on Wisbech. The car was seen travelling towards King's Lynn around the time of the incident.
The girls died at Walsoken when a black Ford Focus left the road and overturned, coming to rest on its side at the edge of a ditch.
It happened about 500 metres north of the Broad End Road junction as the vehicle travelled towards Wisbech.
Tamzin and Jessica Portor, aged 10 and seven and from Sutton Bridge in Spalding, died from their injuries.
Three other people travelling in the car, a 12-year-old boy, 38-year-old man and a 43-year-old woman, all suffered minor injuries.