The boys at work, ever sympathetic and supportive of my various plights, loved the idea of a knitting death threat and began to speculate on other ways knitters could bring about each other's demise.
Should you wish to explore all of this further there is a brilliant book by Pamela Branch called "Murder Every Monday". Don't be put off by the cover. I came across it as a green penguin in a charity shop but have read it over and over because the idea is so clever, the writing very enjoyable and the story highly engaging. Also remember that none of the suggestions above talk about how to get away with it afterwards. While there are more and more of us out there every day, restricting yourself to death-by-knit is hugely narrowing the pool of suspects. So, you know, don't try this at home.