Mary's killing of Patrick is by no means an example of pre-planned, premeditated murder. It is a crime of passion, an expression of anger arising from a sense of hurt and betrayal.

Patrick had just informed his loyal and loving wife that he was leaving her for another woman. Mary immediately responded by grabbing hold of the nearest thing that came to hand—a frozen leg of lamb that she was planning to cook for dinner—and hitting him with it, causing his death. There was no rhyme or reason to Mary's choice of weapon; it just happened to be the most convenient object.

The lack of planning involved in Mary's killing of her husband stands in stark contrast to the cool, calculated, and methodical manner in which she goes about covering up her crime. As well as heading off to the local grocery store to establish an alibi, she also serves up the murder weapon for dinner to the police officers investigating her husband's killing.

Although the use of the frozen leg of lamb as a murder weapon may not have been planned, it's turned out to have been most fortuitous for Mary. If she'd used another weapon, it's likely that she would've been caught.

Why did Mary kill Patrick with a leg of lamb in "Lamb to the Slaughter"?

"Lamb to the Slaughter" was published in 1953. Those were the days when Americans were buying big freezers in which they stored many different kinds of frozen meats--steaks, chops, roasts, etc. It was believed that they could save money in the long run by purchasing meat wholesale. The freezers were so big that they were usually kept in the garage or down in the basement. They have lost their popularity for several reasons. For one thing, if there was a power outage due to a storm or some malfunctioning in the generators, the meat might spoil and result in a loss rather than a saving. Also, refrigerators came on the market which had big freezer compartments, and these appliances have pretty much replaced the big coffin-like freezers in Americans' homes. Furthermore, the cost of electricity had to be subtracted from the savings on the meat, and many people felt that frozen and thawed meat did not taste as good as fresh meat.

Mary did not intentionally select the leg of lamb as a weapon. She just happened to have it in her hand.

"I'll fix some supper," she whispered. When she walked across the room, she couldn't feel her feet touching the floor. She couldn't feel anything except a slight sickness. She did everything without thinking. She went downstairs to the freezer and took hold of the first object she found. She lifted it out, and looked at it. It was wrapped in paper, so she took off the paper and looked at again --- a leg of lamb.

A frozen leg of lamb would make an excellent blunt instrument for committing a murder. It would weigh perhaps eight pounds and would have a big bone at one end which would serve as a convenient handle. Mary succumbed to a sudden impulse. If she had been holding a steak or a roast instead of that leg of lamb, it probably wouldn't have occurred to her to hit her husband over the head. But the leg of lamb was perfect for the purpose.

If Mary had somehow been accused of the crime and convicted, she would not have been charged with first-degree murder. The crime was not premeditated. It would have been impossible to prove that she even intended to kill Patrick because, in fact, she probably did not even know she was capable of killing him with that leg of lamb. She may have only intended to hit him. She would have been charged with second-degree murder or manslaughter.

Weapons often seem to have lives of their own. Murders are often committed just because the weapon is available. The frozen leg of lamb seems to have the power to produce the crime, just because it is such a convenient weapon and is so easy to dispose of. When Mary puts it in the oven, the enticing smell of a roasting leg of lamb permeates the whole household. The investigating police officers can't resist it. It is the perfect weapon for the perfect crime.

Mary had no intention of killing her husband when she took the leg of lamb out of the freezer. She didn't even know she had selected a leg of lamb until she removed the paper wrapping. What triggered her violent action was her husband's dismissal of what might have been their last meal together.

"I've already told you," he said. "Don't make supper for me. I'm going out."

He has his back turned to her. He is ignoring her. It is as if he has already dismissed her from his life. He might go out and never return. He was not only rejecting her but rejecting the baby she was carrying in her womb.

At that point, Mary Maloney simply walked up behind him and without any pause, she swung the big frozen leg of lamb high in the air and brought it down as hard as she could on the back of his head. She might as well have hit him with a steel bar.

Is it credible that such a meek and loving woman could commit such a violent murder?

"Heaven has no rage like love to hatred turned, Nor hell a fury like a woman scorned,"  
                                                      - William Congreve