The “racist behaviour” happened on 9 July between 18:25 and 16:45 on the ‘91’ bus service.
At this time, while the bus was travelling from Pembroke Bay to Town, “a white passenger used racist behaviour towards a black passenger” according to Guernsey Police.
They said: “Anyone that saw the incident take place or who might be able to identify the individual responsible should contact PC 67 MANNING at Police Headquarters on 01481 222 222 or Crimestoppers, anonymously, on 0800 555 111.”