PC 28 Shields is investigating the incident, in which the victim is described as a “juvenile male”.
The assault happened on Fountain Street, St Peter Port, at around 17:00 on Monday 5 September.
Guernsey Police said that “during this incident, multiple members of the public were present, both juvenile and adult and Police are keen to speak with anyone who may have witnessed all or part of it”.
Any witnesses or anyone with information should PC 28 Shields or PC 159 Bourgaize on 222 222 or Crimestoppers anonymously on 0800 555 111.
Pictured: Fountain Street.