Section 3.3: Elements of Crimes

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In order for the government to convict someone of a crime in a court of law, it must be able to prove the legal definitions of that crime. These definitions include certain specific elements that are necessary for the crime to have occurred.

Video Overview

Video Overviews of Section 3.3 are available on YouTube:

Section 3.3.1: Elements of Crimes (Part 1)
Section 3.3.2: Elements of Crimes (Part 2)

However, not all crimes have the same specific elements, as some only apply to specific types of prohibited harmful actions. For example, one element may only apply to theft, while another applies to assault.

It’s important to note that even small differences in the elements of a crime can change the severity of the offense. For instance, a particular type of crime may have different degrees of severity, such as first-degree murder and second-degree murder. These different degrees of severity are often distinguished by the presence or absence of certain elements of the crime.

An example of this is the distinction between manslaughter and murder. At common law, the mental element of malice aforethought was the distinguishing factor between these two offenses. Malice aforethought refers to the mental state of the perpetrator at the time of the offense.

If the perpetrator acted with the intent to kill or with reckless disregard for human life, it was considered murder. If, on the other hand, the perpetrator acted without malice aforethought, it was considered manslaughter.

Understanding the elements of a crime is crucial to understanding the legal system and how criminal cases are prosecuted. By proving the necessary elements of a crime, the government can obtain a conviction in a court of law.  Each crime is defined by its own specific elements.  However, all crimes can be understood in terms of general elements that all crimes have in common.  

The Criminal Act

The law has certain rules that define what is considered a crime. If the government cannot prove that all the elements of a crime exist, they cannot get a conviction. Different crimes have different elements. Sometimes just one element can make a crime different from another similar crime. As in the above example, in the past, the difference between murder and manslaughter was the mental element of malice aforethought.

Criminal law doesn’t care about what you think or say as long as it is within limits. It only cares about what you do. Lawyers use a Latin phrase called actus reus to describe this element of a crime. Actus reus means the guilty act. The term act can be confusing because it’s usually thought of as an action that someone does. However, the law can also punish people for not doing something they are supposed to do. This is called an omission. For example, if a parent doesn’t feed or shelter their child, they have committed an offense based on omission. If someone doesn’t pay their taxes, that can also be a criminal offense.

In addition to acts and omissions, possessing something can be a criminal offense. Possessing certain weapons, drugs, or burglary tools can be illegal. There are two types of possession: actual possession and constructive possession. Actual possession is when someone physically has something, while constructive possession is when someone has the knowledge and ability to control the object.

Threatening to do something or attempting to do something can also be considered part of the guilty act. Remember, criminal law is concerned with what you do, not what you think. The law has certain rules that define what is considered a crime. If the government cannot prove that all the elements of a crime exist, they cannot get a conviction. Different crimes have different elements. Sometimes just one element can make a crime different from another similar crime. 

Criminal Intent

One of the most fundamental principles of the law is that to convict someone of a crime, there must be both a guilty act and a mental state that shows they are blameworthy. This mental state is known as mens rea, and many different legal terms describe it. However, the Model Penal Code simplifies this by breaking mens rea down into four basic types: purposely, knowingly, recklessly, and negligently.

A person acts purposely when it is their conscious goal to engage in the conduct prohibited by the law. They are doing it on purpose. For example, imagine Sarah, a disgruntled employee who decides to steal sensitive company information to sell to a competitor. She carefully plans the theft, breaks into her boss’s office, and takes the confidential documents. In this case, Sarah’s actions are purposeful, as her conscious goal was to steal the information and profit from it.

A person acts knowingly when aware that their conduct will cause a particular result, even if it wasn’t their primary goal. They knew what would happen. Consider the case of Mark, a chemistry teacher who creates a powerful acid to clean stubborn stains in his laboratory. While mixing the chemicals, Mark realizes that the acid could also be used to dissolve metal locks. He mentions this to a friend who later uses the information to break into a warehouse by dissolving the lock. Although Mark’s primary goal was not to assist in a crime, he acted knowingly by sharing information that he was aware could lead to criminal activity.

A person acts recklessly when they consciously disregard a substantial and unjustifiable risk, meaning they knew a risk involved, but they did it anyway. Take the example of Alex, a driver who speeds through a residential area well above the posted speed limit, fully aware that children often play on the sidewalks and streets in the area.

Alex’s decision to drive recklessly poses a substantial risk to the safety of others, yet he chooses to ignore the potential consequences of his actions. His behavior demonstrates a reckless disregard for the safety of the children and other residents in the neighborhood.

And finally, a person acts negligently when they should have been aware of a substantial and unjustifiable risk, but they were not aware. Suppose Jane, a restaurant owner, stores raw meat and vegetables in the same refrigerator.

Jane fails to educate herself on proper food handling procedures and remains unaware of the risks associated with cross-contamination. If a customer falls ill due to food poisoning from her restaurant, Jane could be held responsible for her negligence in not understanding and adhering to proper food safety practices.

Let’s recap these complex concepts: The four culpable mental states are purposeful, knowing, reckless, and negligent. A person acts purposely when their conscious goal is to engage in conduct prohibited by the law, as demonstrated by Sarah’s intentional theft of company information.

A person acts knowingly when they are aware that their conduct will cause a particular result, even if it wasn’t their primary goal, as illustrated by Mark’s sharing of information on a powerful acid.

A person acts recklessly when they consciously disregard a substantial and unjustifiable risk, as evidenced by Alex’s dangerous driving in a residential area.

And finally, a person acts negligently when they should have been aware of a substantial and unjustifiable risk but were not, as in Jane’s case of improper food handling practices. Each mental state demonstrates a different level of awareness and intent, all of which can potentially result in criminal liability.

Sometimes, the legislature intentionally excludes the mental state element from a criminal offense. This means that only the guilty act is necessary to define the crime. These are known as strict liability offenses, often involving minor violations such as speeding. In these cases, the officer does not need to prove that the person intended to speed, only that they were speeding.

This is because requiring a mental element for such minor violations would be too burdensome on law enforcement and the courts. However, there are a few serious felony crimes that are also strict liability offenses, such as statutory rape laws in some states.


In the context of criminal law, concurrence refers to the requirement that the guilty act (actus reus) and the guilty mind (mens rea) must occur at the same time. In other words, for an act to be considered a crime, it must be accompanied by the intent to commit that act. This is a fundamental principle of criminal law.

Consider the following hypothetical scenario:  

Jim, a 45-year-old man, had always harbored a strong dislike for his neighbor, Tom. Tom’s late-night parties and constant noise disrupted Jim’s peace, and he had reached his breaking point. One day, while browsing the internet, Jim stumbled upon a recipe for a homemade explosive. Out of curiosity and anger, he decided to create the explosive in his garage with the intention of using it to destroy Tom’s sound system.

Jim carefully followed the instructions, and after a few hours, he had successfully created the explosive device. However, he had no immediate plans to use it, so he locked it in a safe in his garage and went to bed.

That same night, a burglar broke into Jim’s garage, looking for valuable items to steal. The burglar discovered the safe, managed to crack it open, and found the homemade explosive inside. Intrigued, the burglar took the explosive and, on a whim, decided to use it to blow up a nearby ATM to steal the cash inside.

In this hypothetical example, Jim created the explosive with the intent to commit a criminal act, but there was no concurrence between his intent and the subsequent criminal action. The burglar, not Jim, committed the criminal act of blowing up the ATM, and Jim had no knowledge or involvement in the burglar’s actions.

Thus, while Jim’s initial intentions were potentially criminal, the lack of concurrence between his intent and the criminal act prevents him from being held responsible for the ATM explosion. (Of course, the manufacture and possession of explosives is a separate crime).

The concept of concurrence is important because it ensures that individuals are not punished for actions they did not intend to commit. In the example, since the intent to steal did not exist at the time of breaking and entering, there is no concurrence between the guilty mind and the guilty act, and therefore no burglary has been committed.

Criminal Harm and Causation

In criminal law, causation is a fundamental concept that refers to the relationship between a person’s behavior and a negative outcome. Causation is an essential element of a crime, especially in cases where the criminal law requires a prohibited outcome, such as murder. In such cases, the harm caused by the actus reus must be directly linked to the prohibited outcome.

For instance, in a murder case, the prosecution must prove that the defendant’s actions, such as shooting or stabbing someone, directly caused the victim’s death. The prosecution must establish a causal connection between the defendant’s actions and the victim’s death. If there is no causal connection, there can be no conviction for murder.

In other words, the defendant’s behavior must be the “cause in fact” of the prohibited outcome. Cause in fact refers to the idea that the defendant’s actions were a necessary and sufficient condition for the prohibited outcome to occur. If the prohibited outcome would have occurred anyway, regardless of the defendant’s actions, then there is no causal connection between the defendant’s actions and the prohibited outcome.

For example, if a person is already dying from a terminal illness and the defendant shoots that person, and the person dies from the terminal illness instead of the gunshot wound, then the defendant’s actions were not the cause in fact of the person’s death. Therefore, the defendant cannot be convicted of murder.  (That doesn’t mean his act wasn’t criminal; he is still guilty of shooting the person, just not killing them).



American Law Institute. (2017). Model Penal Code: Official Draft and Explanatory Notes. Philadelphia, PA: American Law Institute.

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Last Updated:  07/13/2023

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