A Guernsey medical group has confirmed it experienced a "cyber incident" which affected their email system in December 2021.
It resulted in a number of patients and contacts receiving emails claiming to be from the Guernsey's Medical Specialist Group (GMSG).
Jon Buckland, chief executive of GMSG, confirmed a police investigation is underway.
He offered his "sincerest apologies", and has notified those affected.
Mr Buckland said the group's emails were "immediately re-secured" and he takes cyber security and data protection "incredibly seriously".
He said: "I would like to offer our sincerest apologies for any inconvenience or concern this incident has caused."
The chief executive said the group was continuing to work with the police and the information security officer of the States of Guernsey.
"As the police investigation continues, we hope to be able to determine those behind the incident and inhibit any further criminal activity," he added.