Thames Valley Police is appealing for witnesses or information following a robbery in Abbey Meadow, Abingdon on Saturday (15/4).
At approximately 6.30pm, a group of four teenagers in their late teens were involved in a verbal altercation with a 14-year-old boy who was on his bicycle.
The boy was then hit around the head and arm with an object, believed to be a metal D lock, and one of the group then cycled off on the victim's bicycle.
It is believed that a member of the public attempted to intervene but was intimidated away by the group.
The bike was later found in a bush and returned.
The male who took the bike is described as a teenage boy, around 5ft 8ins, slim, with medium length brown hair. He was wearing dark clothing.
The victim sustained injuries to his arm and his bicycle helmet was damaged from the assault. He did not require hospital treatment.
Investigating officers would like to speak to anyone who witnessed the incident. If you have any information, please call PC Josh Hatton from Abingdon Police Station on 101, quoting reference 43170109231.
A 15 year-old boy from Abingdon was arrested on suspicion of robbery. He has been released under investigation.
If you have any information relating to this case, please call 101 or contact Crimestoppers anonymously.