In "Yellow Iris" there are reasons to think that a certain person was innocent when really he was the murderer. And last but not least in the story "Witness for the Prosecution" you really start to believe that suspect character is innocent when really he guilty.
Christies story "How Does Your Garden Grow" is about a detective named Hercule Poirot who receives a letter from an old women named Amelia Barrowby which says that she has some suspicions about a personal matter that which she does not which to write in the letter. She wants to meet with him. When he has his secretary write a letter back they come to find out that the old lady has died. This leads Poirot to investigate the situation. He goes over to the house and sees a garden in the front and it reminds him of a childhood rhyme which goes, "Mistress Mary, quite contrary how does your garden grow? With cockle-shells, and silver bells, and pretty maids all in a row."(50) This is a clue for Poirot towards the end. He then sees a person at the door who was the old ladies personal caretaker, Katrina. She prepared everything for the old lady. She is the person who Amelia Barrowby left her money to. In the house also lived Mr. and Mrs. Delafontain. Mrs. Delafontain was Miss Barrowby's niece. This couple was pretty poor. All the evidence lead to Katrina killing Miss Barrowby. Reasons that lead to this was that Miss Barowby was always bossing her around. Inspector Simms had said, "Yes. Katrina Reiger. She was a kind of lady help, nurse-companion to Miss Barrowby. Fairly ordered about by her, too, I gather. Fetch this, fetch that, fetch the other, rub my back, pour out my medicine, run round to the chemist, all that sort of business. You know how it is with these old women they mean to be kind, but what they need is sort of a black slave!"(57) Other evidence leads to her when they think Katrina had poisoned her by putting poison in her cachet.