Lamb to the Slaughter

At the end of “Lamb to the Slaughter” by Roald Dahl, Mary Maloney begins giggling because she killed her husband with a frozen leg of a lamb, after he said that he was leaving her. She hit him in the back of the head with it a smashed his skull. Then she put the leg in the oven to cook. When the police came, they sent hours looking for the weapon. Mary began giggling when she convinced the policemen to eat the lamb and while they were eating it they were saying that it was probaly right under their nose and it really was. She was luaghing because they never suspected that she was the murderer of her husband. She could have also been giggling because she knew that they were never going to find the weapon because they had just eating it.