Details remain limited, about the latest Police investigation into murderer and prison escapee Philip John Smith

The probe was revealed during Smith's 14th parole hearing yesterday, where he was again denied release.

The Parole Board didn't know the nature of the investigation, but Police have told the Herald's Open Justice, it relates to complaints from members of the public.

Meanwhile, Smith's security classification has been raised from low-medium to high.

It follows revelations two mobile phones were found in Smith's cell, and a lighter was hidden in a pack of porridge.