Police in Edinburgh are appealing for witnesses following a serious road collision in the Meadows area.
The incident happened around 3.15am on Monday 17th December at Hope Park Terrace.
An Audi S3 car overturned resulting in four of the occupants sustaining various injuries.
The three women aged 19,20 and 25, and one man aged 36, were all taken to the Royal Infirmary where they continue to be treated.
Road Policing Officers responded to the scene and local road closures are still in place while they conduct their investigation.
Sergeant Iain Blain from the Road Policing Unit in Edinburgh said: "At this time, we do not know what has happened to result in the car overturning.
"However, we believe that another male and female exited the vehicle and left the scene before emergency services arrived.
"Both of these individuals could be seriously hurt and in need of medical attention and so anyone who can help us identify and trace them is asked to come forward.
"Despite the early hour of the morning, The Meadows is often still frequented by joggers dog walkers and other members of the public. As such, we'd ask that anyone who witnessed this incident to contact police immediately.
"Similarly, any motorists with relevant dash-cam footage, or those with any other information relevant to this inquiry is also urged to get in touch."
Those with information can contact the Road Policing Unit in Edinburgh via 101 and quote incident number 357 of the 17th December.