Georgie (The Devil of Winterborne)
Talk about it here.
Georgie was the gardener at Winterborne School. Apparently simple-minded and teased by the schoolboys for his stammer, he was nevertheless capable of telling Liz Shaw some very useful information when required. Georgie knew that both the present headmaster, Gavin Purcell, and the former headmaster, Mr Whittaker, were involved in bizarre occult rituals in the school. He also knew that a third person, whom he didn't recognise, was their leader. The members of the the cult had beaten and threatened him to ensure his silence. As the rituals spiralled into murder, Georgie eventually broke his silence. The leader turned out to be schoolboy Christian Purcell. (HOMEVID: The Devil of Winterborne)
Some months later, when both Purcell and the ritual murders briefly returned to Winterborne, Georgie was unseen. He preferred to remain in his cottage after all the traumatic events. (HOMEVID: Ghosts of Winterborne)