Laura Lyons is the key lead to the unraveling of the mystery who constructs herself as the innocent victim. How far do you think the readers are convinced about her lack of involvement ?

Sir Charles had been helping Laura Lyons extricate herself from an unhappy marriage that she had contracted in haste. It was Mr. Stapleton, whom she considered to be a neighbour and intimate friend of Sir Charles who had spoken to Sir Charles about her in kind words and with great concern.

Holmes' had alleged that Stapleton and his wife were murderers of Sir Charles. He had done so in front of Mrs Laura Lyons so that the latter would confess the nature of their crimes on her own upon learning the truth about Stapleton. Holmes told Mrs Lyons that the case had now been established to be a murder and that not only Stapleton but also his wife were to be implicated. This took Mrs Lyons by surprise because she like others had not been aware of the fact that the woman who was projected as his sister was actually his wife. As Mrs Lyons came to know of this fact,she decided to reveal the truth to Holmes on her own volition. She told him about how Stapleton had offered her marriage on condition that she could get a divorce from her husband and lied to her in every conceivable way. She had been used merely as a means to an end therefore, she decided that she would return the favour by not shielding him from the consequences of his wicked acts. She confessed that she had been forced to write the letter to Sir Charles by Stapleton even though she had wished him no harm and only on the expectation that the old gentleman would help her with legal expenses for her divorce. She had been made an accomplice in the murder of Sir Charles without having any knowledge of the fact. Had it not been for the letter, Sir Charles would not have ventured out towards the moors on the night before his journey and might have been alive.

Stapleton had led Mrs Laura Lyons to believe that he was unattached and that once she obtained a divorce from her husband, they would be free to marry. Mrs Lyons was a mere tool in his hand whom he could use as he pleased. So when he learned that Sir Charles would be leaving the Hall, he made use of his power over her by putting pressure on Mrs Lyons to write a letter to Sir Chares asking him for an interview in order to help her out with her divorce. Then he prevented her from going to meet him and the ground was laid for him to act. She was nothing but a tool in his hands whom he had manipulated without any moral compunctions. She had not even dreamed of the fact that she had been party to a murder. So it is evident that Stapleton had acted like the villain that he was and used all his resources to fool the poor woman.