In your judgement who is most responsible for Dr Roylott's death in "The Adventure of the Speckled Band" by Arthur Conan Doyle?

Dr Roylott himself is largely to blame for his own demise. He has the fatal flaw of greed for the money bestowed on his stepdaughters and uses violent means to bring about the death of one of them, Julia. It is only through the intervention of the brilliant Sherlock Holmes who uncovers Roylott’s evil snakebite scheme that the second stepdaughter, Helen, is not killed also. There is a neatness in Roylott’s death being due to the very snakebite he intended for his stepdaughter: poetic justice indeed.