Question

how did holmes find the person who send a newspaper cutting letter to henry

Answer 1

Holmes inferred that the newspaper cutting was by a woman or Stapleton's wife who had had an inkling of his plans to harm Sir Henry. But she had such a fear of her husband that she did not dare to warn the man whom she knew to be in such danger by writing. Hence the letter with a message in the form of newspaper cuttings,to ensure that even if the letter fell into Stapleton's hand by any chance, she would not be in danger. Therefore, she adopted the method of cutting out words from the newspaper which would form the message and addressed it in a disguised hand.