Detectives are investigating the possibility that a woman who was killed in a crash was deliberately pushed into the road.
The pedestrian, who is yet to be named, suffered multiple injuries when she was hit by a silver Kia on the A47 at Terrington St John in Norfolk.
A male pedestrian also died from severe head injuries after the incident on the eastbound carriageway at 2.15pm on Sunday.
Detective Chief Inspector Paul Durham confirmed that the incident was being treated as suspicious, with the main line of inquiry focusing on evidence that the woman was "forcibly pushed".
He added: "Although our investigation is in its early stages, initial inquiries have given me sufficient cause for concern that this was more than just a tragic accident.
"As a result I'm appealing to anyone who was in the area at the time and may have witnessed the collision - or seen the two pedestrians shortly before the collision - to come forward, no matter how insignificant the information may seem to them."
The man is described as white, 6ft 1in and of slim build, with short dark hair. He was wearing blue denim shorts and a grey T-shirt.
The woman is described as white, 5ft 7in and of slim build, with long auburn- coloured hair. She was wearing a bright pink T-shirt and black knee-length leggings.
It is believed that the pair may have been walking barefoot towards King's Lynn.
Anyone with information should contact the Norfolk and Suffolk major investigations team on 101.