Patrick came home from work and Mary was very polite to her spouse. They both talked while drinking. Mary wanted to be helpful but Patrick told her no.
Mary went down to the freezer and took out a leg of a lamb. Then, without thinking, she smacked Patrick in the head with the leg and killed her husband.
Mary tried to act normal as she then went to the store and asked Sam, the store clerk, to get her a few items like potatoes, and a cake.
Mary came home and saw Patrick on the ground. She snapped back into her loving life and cried next to him. She then called the police and told them about coming home and discovering Patrick on the floor.
Officers and doctors came to Mary's house. Mary said that she came home and found Patrick dead, the doctor concludes that Patrick is dead. They theorize that someone broke in, hit Patrick with a steel bar, and left.
Mary then invites the visitors a drink and supper. They agree and Mary cooks lamb, she uses the same leg of lamb that she killed Patrick with. The officers discuss about the crime and exclaim that "The weapon could be right under our noses". And it was.