Two 15-year-olds were robbed as they walked along a road in Northampton on Saturday evening (December 6).
The teenagers were approached at about 8.35pm in Fullingdale Road, assaulted and had a green iPhone 5C stolen.
There were three offenders, all men aged in their late teens to early twenties. All three were between 5ft 10in and 6ft and were black or mixed race.
One was wearing a red hat and had some red on his jacket.
All three offenders made off to a footpath between Fullingdale Road and Broadmead Avenue, and then to Grange Road, before heading in the direction of Newby Court.
Police officers would like to speak to anyone who may have witnessed this incident or have any information regarding it.
Witnesses or anyone with information is asked to contact police on 101 or Crimestoppers anonymously on 0800 555 111