‘I lived in a state of terror’: Patricia Cornwell on childhood trauma, her new novel and the search for big foot. Cornwell's father walked out when she was five. Her mother suffered from severe depression and wasn't able to look after her or her siblings properly. The mother became obsessed with Billy Graham and moved to where he lived. Two years later she had a breakdown and the Graham's took them in whilst a foster family was found. The foster mother was cruel to Cornwell. The breakdowns continued and the children moved in and out of foster care.