Fear the Light (Murder Room)

Alice Robertson was now too old and frail to cope with the stairs. But when Charles Robertson returned from an evening stroll he found something had made her tackle them once more - with tragic results. There were few people with a motive for the old lady's death. But then a rumour spread that in the house, forgotten for generations, were objects that had belonged to the first James Robertson. Someone had rediscovered them, recognised their value - and killed for them.