As a Detective

  The story " Lamb to the Slaughter" by Roald Dahl informs the readers  a perfect crime which is impossible to solve. Can the son of Conan Doyle, Sherlock Holmes , clear this case ? Well, Roald has given two significant facts which convince the audiences the fact that Mary is never suspected by the police because of her tied relationship with them, being pregnant,  and the eaten weapon-the most persuasive one.  If the polices get"the weapon", they have "the man". There is a possible way prove her a suspect but a perpetrators. 

    Mary makes her a mistake when calling the police station first instead of the hospital. As an innocent woman, she would find her way ,somehow, to save her husband. Calling the police confirms the fact that she already know he's dead. She may argue that is common sense to do so. However perhaps he is just unconscious . The faster she contacts the hospital, the higher chance he may survive. Second, beside the  lamb leg, she forget there are " plenty of meat in and stuff in the freezer"(Roald). When the polices ask her whether there are metal object in her house, she is uncertain about this. The doctor notices the "small patch of congealed blood " on her husband. Logically , the time the death occurs is close to the time she is leaving the house. There is no broken windows and door corroborate that there is no one sneaking in the house. Next she convinces the cop to drink whisky and to eat lamp. Sitting on the chair, not moving any where , she is afraid of her fingerprint on the crime scene.