A woman who was critically injured in a collision with a police van at Hethel on Thursday has died.
The incident happened at about 10.20pm on the B1135 Wymondham Road when a marked police van and a pedestrian were involved in a collision.
In a brief statement police confirmed that the woman had died earlier this morning after sustaining serious injuries.
Officers were in the area responding to a 999 call relating to concerns for the safety of a woman who had been reported missing when the incident occurred.
The woman was airlifted to Addenbrooke's Hospital for treatment, but was said to be in a serious condition.
Norfolk Constabulary has referred the matter to the Independent Police Complaints Commission (IPCC), which has begun an independent investigation into the incident.
An IPCC spokesperson said: 'An incident involving a collision between a police vehicle and a pedestrian on Wymondham Road, Norfolk on 27 July has been referred to the IPCC and an independent investigation has begun.
'The investigation is at a very early stage and we will continue to gather evidence over the coming weeks.'
The identity of the woman has not been released yet, however she is said to be in her 50s.
She had been reported missing over fears for her own safety.
Two ambulance crews and an ambulance officer were called to the scene and treated her for complex serious head injuries and leg injuries.
She was taken to hospital by the East Anglian Air Ambulance (EAAA).
The helicopter was piloted by Prince William, who was working his last shift before leaving the life-saving charity.
An EAAA spokesman said: 'The EAAA crew, which included William, attended an incident south of Norwich which involved a road traffic collision-related injury.
'A patient was treated at scene for severe head injuries then treated at Addenbrooke's Hospital.'
The road remained shut for nearly 17 hours before reopening just after 3pm on Friday.
The air ambulance returned to its Cambridge base at 1.30am, at the end of Prince William's final shift.
The Duke announced in January that he would be ending his career with EAAA after spending more than two years flying medical crews to emergencies.
An IPCC spokesman said they had not ruled out interviewing him as part of their investigation.
The spokesman said: 'When conducting investigations, the IPCC often works closely with the emergency services as well as other partner organisations to obtain relevant evidence.
It is therefore entirely possible in this investigation that witness statements may be required from employees working with the emergency services outside of Norfolk Police but thus far there has been no indication that this will be necessary.'
William joined EAAA as a pilot in March 2015. After completing an initial period of job-specific training involving simulator, aircraft and in-flight skills, he began piloting his first operational missions in July 2015.
Throughout his service, he had been based at Cambridge Airport, as part of a team including specialist doctors, critical care paramedics and pilots providing emergency medical services across Bedfordshire, Cambridgeshire, Norfolk and Suffolk.
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