Former soldier and builder Paul Taylor, 60, originally from Peterborough and now of Valentine Close, Fareham, Hampshire, was arrested last year following a cold case review.
Today, at Chelmsford Crown Court, a jury found him guilty of murder following 23 hours of deliberation.
He was found guilty of three counts of rape, one attempted rape and a serious sexual assault, which were all committed in the months leading up to Miss McGrath's murder
More top news
Early fog will clear to leave a dry day with sunny spells and highs of 18 deg C (64 deg F)
Overnight there'll be mist and fog but it will clear for Sunday leaving sunny spells.
A month of special events for the Norfolk nurse responsible for saving Allied soldiers in the First World war, has begun.