A case of Covid-19 with an "unidentified source" has been confirmed in Guernsey.
The States of Guernsey said the positive test was returned on Monday evening. Earlier in the day it was announced there were no current known cases in the island.
Public health officials said they were working with the infected individual "to establish the exact source".
Since 27 May, all Guernsey's cases have been identified in inbound travellers.
Director of Public Health Dr Nicola Brink said: "It is unusual to pick up a case of Covid-19 in the Bailiwick where the source is not immediately obvious.
"However, our track and trace team have robust and well tested processes in place so it should not be long before the exact details are established."
She said an employer "associated" with the case had closed its offices.
The infected person, of working age, is not in hospital.
It brings the total number of Covid cases seen in the island to 259, most of them in the first wave of infections.