An appeal to trace the woman is now ongoing as part of an inquiry into a fatal road collision at the Maybury Roundabout in the early hours of Friday, 25 May.
Officers are also hunting for a small hatchback vehicle that travelled north from the Maybury Roundabout, towards Barnton, just before he collision.
Police believe the driver of the hatchback may know vital information.
The individuals have yet to be traced and have been asked to come forward.
Eyewitness statements now confirm a woman, who was not involved in the collision, attended the scene after the incident and administered medical assistance to those within the BMW X5.
It is believed this woman was a doctor or health professional. She has been urged to contact police immediately.
The woman is described as being white with blonde hair.
Officers would also like to thank the public for their response to this inquiry. A series of people have got in touch with various pieces of information that are all being progressed.
Detective Inspector Graham Grant said: “The woman who came to the aid of the injured family in the BMW was not in any way involved in the collision, but obviously saw the aftermath and provided vital assistance.
“We would like to speak to this individual as a matter of urgency and would ask she make contact with us.
“The public have been absolutely incredible in coming forward with information to assist our investigation. Since releasing the registration number that was on the stolen Audi A3, we have received numerous calls from people having seen a vehicle with this plate.
“I’d like to reassure our communities that the vehicle currently displaying this registration number is the legitimate vehicle. The stolen Audi, which we recovered in Cowdenbeath, was using cloned plates at the time and what we remain keen to establish is the movements of this car between 17 April and 25 May.
“If you believe you have any relevant information then please come forward.”
Those with information can contact Corstorphine CID via 101 or make an anonymous report to the charity Crimestoppers on 0800 555 111.