Armed officers were called to the A11 on Sunday after a man was seen leaving a crash in London Road, Thetford, holding what was described as a handgun.
A witness said they saw the man “point a gun at a girl” before running through the nearby Redcastle Furze housing estate.
The A11 was closed for most of Monday following the shooting (Image: East Anglia News Service)
He was then seen on the southbound carriageway of the A11, near the Brandon Road roundabout, walking in a northbound direction.
Armed officers fired two shots at 9pm and he was pronounced dead before 10.15pm, despite the efforts of emergency services.
What appeared to be a non-police issue firearm was recovered from the scene.
A post-mortem examination following his death took place on Friday and he has been named as Tony Keeble, aged 61, from Thetford.
The provisional cause of death has been given as gunshot wounds to the chest and abdomen.
A date for the opening of the inquest is yet to be scheduled.
The A11 at Thetford was closed by police (Image: East Anglia News Service)
Following the incident, Norfolk Constabulary referred itself to the Independent Office for Police Conduct (IOPC) and an investigation was launched.
The IOPC probe has so far found that Mr Keeble was ordered to drop his weapon.
The shots were fired by two armed officers and all officers involved are currently being treated as witnesses.
There is currently no indication that any officers breached the police standards of professional behaviour.
IOPC director Amanda Rowe said: “We understand that any incident of this nature is likely to cause public concern, particularly in the local Norfolk community, with questions about the circumstances surrounding this event.
“That’s why it’s important that we carry out a robust and thorough independent investigation.
“Our investigation remains in its early stages and we are still gathering and reviewing evidence as we work to establish the full circumstances.
“Our sympathies remain with everyone affected by this incident.
“We have contacted Mr Keeble’s family and will be meeting with them to explain our role and ensure they are kept updated as our investigation progresses.”