Dyfed-Powys Police said the incident was identified on 14 September, and an investigation had been going on into the circumstances surrounding it.
The force said it remained fully operational and its response to emergency incidents had not been affected, adding that while online and email contact services were unavailable for a period, these had now been restored, and 999 and 101 service had not been affected.
The Information Commissioner's Office (ICO) has been notified.
This breaking news story is being updated and more details will be published shortly. Please refresh the page for the fullest version.
You can receive Breaking News on a smartphone or tablet via the BBC News App. You can also follow @BBCBreaking on X, external to get the latest alerts.
