A 13-year-old was punched in the face before having his mobile phone stolen in Hazeley on Tuesday.
Police are appealing for witnesses after the incident which took place on the redway between Hazeley and Grange Farm at around 4.20pm.
The teen was walking when the offender approached him from behind before punching him in the face, knocking him over. He then searched his pockets and stole a Samsung Galaxy 3 phone.
The offender is white, early twenties, about 5ft 8ins, heavy build with short brown hair. He was wearing a white top with a company logo beginning with the letter K on the front left handside.
The teen suffered swelling and a cut to the eye but did not need to go to hospital.
Three people who were standing nearby when the incident happened are being urged to call police on 101 or Crimestoppers, anonymously, on 0800 555 111.