In "Lamb to the Slaughter," how can I prove that Mrs. Maloney is guilty of killing her husband, even after the police eat the murder weapon and...

In all courts of law, there are two types of evidence that are allowed to be presented as proof that a crime has been committed. They are direct evidence and circumstantial evidence. 

Direct evidence would be the items that your question refers to, namely, the tangible and directly visible items that are either in, or connected to, the scene of the crime. These are: the leg of lamb, the testimony of Mrs. Malone, the testimony of those who saw her at the store, and other things that directly link one item, or cause, to the crime. 

Circumstantial evidence is evidence which is inferred from the testimony, even when there is no direct evidence present. This is why people such as Scott Peterson, for example, was found guilty of murder in the first degree for the killing of his wife, Laci Peterson, and her unborn son, even though there was no murder weapon and no powerful witnesses to place him at the scene of the crime. Instead, what was used was the set of circumstances surrounding the murder, and the little direct evidence available, to create the scenario that would establish a motive (reason to commit the crime), the opportunity, the timeline of events, and the unquestionable reasons why he would have been the one committing the crime.

Remember, the investigators put the evidence together. The defense lawyers will create, using the evidence, a version of the crime that would benefit their accused client. The prosecution will take that same evidence and create a storyline that directly places the accused on the scene, with a motive, and with the opportunity to commit the murder. It is ultimately up to the jury to decide which story to believe based on what they see. 

All of this, however, needs to be presented in a way that, there is NO QUESTION from the jury that the person is guilty or not guilty: beyond reasonable doubt. No jury is perfect, however. They can get it wrong, too. 

Mrs. Maloney

The case of Mrs. Maloney would be a circumstantial case given that the murder weapon has been eaten, and that none of the law enforcement agents present in the scene have any intention of accusing her. They are likely not to serve as witnesses of the case, either, so you will need to go elsewhere to find witness testimony in the first place. 

Therefore, when working with a circumstantial case such as Mrs. Maloney's, according to the New York Court Circuit, 

Before you may draw an inference of guilt, [it] must be the only one that can fairly and reasonably be drawn from the facts, it must be consistent with the proven facts, and it must flow naturally, reasonably, and logically from them.

It also shows that, to find her guilty, you would have to find all the factors that would show that she had a good reason to commit this crime, even if it was in the heat of passion. 

Again, it must appear that the inference of guilt is the only one that can fairly and reasonably be drawn from the facts, and that the evidence excludes beyond a reasonable doubt every reasonable hypothesis of innocence.

All this being said, you would need to gather the following evidence and create a timeline of events based on your findings:

• the exact time of death of Patrick Malone. That will show you where to start.

• the reason why he died- It has to be established that it was head trauma that killed him. This is also added to the timeline of events. 

• testimony from Sam, from the grocery store, on whether Mary was there, at what time, and how she looked- You add that to a timeline of events to show that Patrick was already dead by the time Mary decided to go out, presumably to buy items to make him dinner. This will also show that she created an alibi (pretext) by letting herself be seen at the store.

• proof that the Maloney's marriage was in trouble- testimony from Patrick's friends, or any proof of a mistress

• a timeline of how the marriage was, from dating, to now- Is there any pattern of fighting, abuse, or cheating?

• report of what kind of object could have hit Patrick- This way, every possible object can be considered, no matter how outrageous it may sound. 


• deductive reasoning: If Patrick had no enemies, and there was no entry in the house, who else is left to be accused?

Once you are able to get the evidence, answer every possible question that a juror could ask, and create a strong timeline of events, you should be able to establish a clear motive, storyline, and opportunity, that shows, beyond reasonable doubt, that Mary Malone killed her husband in a heat of passion.