From a strictly factual viewpoint, it could certainly be said that Mary Maloney is guilty of killing her husband. There are no other factors at play in the instance of his death that could have contributed to it besides Mary's sudden attack on him. For a crime of passion, his death is surprisingly quick. One strike with the leg of lamb is all that it takes to end his life and to pull Mary out of her state of shock.

It is this state of shock that could evidence a bit of vague innocence. As her husband explains the couple's situation, presumably that he is going to leave her, Mary's mind becomes increasingly detached from reality. She even admits that it feels as though when she snaps out of this state, it will have all been a dream. She continues preparing dinner as though nothing has happened. It is when her husband tells her to stop making him dinner, thereby rejecting her most treasured of domestic duties, that she finally snaps, killing him as instinctively as an animal might.

Ironically, her guilt may have been a point of debate if the authorities had approached the situation at this point. However, everything she does from that moment on paints her in a far more guilty light. She carefully crafts an alibi with a criminality that is almost masterful, and by the end of the story, she is literally listening to the investigating police officers eat the evidence, giggling to herself. She has transformed from a victim to a remorseless murderer.

Mary Maloney is never going to be formally convicted of murder, and so in some ways, she will never really be guilty of the crime of killing her husband. She covers up the murder incredibly successfully, by cooking the evidence to ensure its destruction and by establishing an alibi for herself. She also understands that the local police department would not consider her a suspect because she has preexisting relationships with them. She's so confident that she's completely gotten away with it that when the police, while eating the murder weapon for dinner, exclaim that the weapon is probably right under their noses (completely ignorant of how right they were), she lets out a giggle. It appears that, according to the police and the courts, Mary Maloney is perfectly innocent.

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 just as well have hit him with a steel club.

These words in Roald Dahl's short story "Lamb to the Slaughter" make it crystal clear that Mrs. Maloney is legally guilty of murder.

Whether she is morally guilty is another matter. It is clear that her husband is going to leave her, but we never hear anything of the details. Who is to blame is entirely a matter of conjecture. He promises to give her money and ensure that Mary is looked after, but his dispassionate way of talking may strike many readers as terribly cold-hearted, like the reflection that it wouldn't be very good for his job.

However, even though the story is focalized through Mary's perspective, nothing her husband says or does could be taken as justification for murder—certainly not legally and almost certainly not morally either. The last line of the story suggests that Mary feels no remorse and is rather amused by her own cleverness in getting away with her crime.

Of course she is guilty. That is why she goes to so much trouble to establish an alibi and to dispose of the murder weapon. She is not guilty of first-degree murder because the murder was not premeditated. If all the cops investigating the case knew she was responsible for her husband's death, they would arrest her and take her to jail. No doubt she would make a full confession and would eventually plead guilty. She would be indicted for something like second-degree murder or manslaughter. It is hard to know what would happen to her unborn baby, but it would undoubtedly be taken away from her. We might expect her to serve eight or ten years because of the extenuating circumstances and also because of the fact that she has a spotless prior record. All the policemen themselves could testify as character witnesses.

As readers we are induced to share in Mary Maloney's guilt because we want to see her get away with her crime. We are in a sense accessories after the fact. If we had the power to tell the investigating cops that Mary killed her husband with a frozen leg of lamb--we probably wouldn't do it. Would we? The story is not to be taken too seriously. Mary didn't really kill Patrick. Patrick wasn't really going to leave her. It is just a story. The idea of killing a man with a leg of lamb and then getting the cops to eat the lamb is ridiculous. Roald Dahl was noted for writing stories like this. His story "The Way Up to Heaven" is a good example. Another man who wrote tongue-and-cheek murder stories was John Collier. Good examples are "The Chaser" and "De Mortuis." Such stories always have a touch of humor to suggest that they are taking place in a sort of Never-Never Land where ordinary laws do not apply.