A 27-year-old woman was knocked to the ground and robbed as she walked alone in Lynn in the early hours of Saturday morning.
The victim was walking along Hardings Way heading towards Friars Fleet when she noticed a man walking behind her, shortly before 1.10am.
The man grabbed the victim by the neck and dragged her to the floor. During a struggle the victim was punched in the face suffering minor injuries.
The robber snatched her purse from her handbag before running from the scene.
Investigating officer, Detective Constable Richard Moden, said: “The victim was left very distressed by the incident and immediately dialled 999. Unusually, during this time the robber returned to the scene, handing back the purse to the victim before leaving again. A £10 note had been taken from inside.
“I’m keen to hear from anyone who may have been travelling in this area in the early hours of Saturday and may have noticed a man acting suspiciously.”
Police have said the incident cannot be linked to other recent robberies.
Witnesses should contact DC Moden at King’s Lynn CID on 101 or call Crimestoppers anonymously on 0800 555 111.