Under US law, elements of a crime represent a set of facts that have to be proven beyond a reasonable doubt to convict a defendant of a crime.

While some crimes require additional components (this can also vary by jurisdiction), there are a few critical elements to every crime in the United States. These include actus reus, mens rea, the concurrence of the previous two elements, and causation.

In this article, we will discuss each element, as well as some others, and explain why they are crucial for navigating the United States legal system. If you’re looking to work in criminal law or land a criminal justice job, knowing the elements of a crime is crucial.

What Are the Elements of a Crime?

In the US, crimes are generally broken down into two main categories: Misdemeanors and felonies. For someone to be convicted of a crime (and face the consequences associated with that conviction), there must be evidence proving the defendant committed each element of said crime.

Misdemeanors are less severe crimes punishable by a year or less in jail. Felonies, on the other hand, are more serious offenses that can result in years behind bars (or even life in prison).

Actus Reus (Conduct)

Latin for “guilty act,” this refers to the actual act of committing a crime. No law recognizes thought as a criminal act (yet); hence, for something to be considered a crime, there has to be an act (i.e., conduct) that constitutes a crime in a specific jurisdiction.

For example, if someone is planning to rob a bank, they have not yet committed a crime (as there has been no action). If, however, they were to walk into the bank with a gun and demand money from the teller, this would constitute actus reus, and they could be charged with robbery.

However, the lack of action can also be considered a criminal act. The so-called unlawful omission of an act refers to situations where the defendant was under a legal duty to act. This is usually in cases when a person could've saved another person's life without putting their own in danger. Apart from the often mentioned example of a person drowning while someone was nearby (which is quite tricky to prove), the more common cases of unlawful omission are failure to pay taxes, alimony, child support, or failing to take care of your child. 

Lastly, while thoughts can never be considered a crime, uttered words can. This is a significant exception to the general rule that only physical actions are criminal: Certain acts, like conspiracy and solicitation, comprise an actus reus even if no physical crime was committed (e.g., conspiracy to commit murder).

Mens Rea (Intent)

Mens rea is Latin for “guilty mind,” and this element refers to the defendant's mental state when they committed the crime. To secure a murder conviction, for example, prosecutors must not only prove that the defendant committed the offense, but that they intended to do so. If this cannot be proven, either because the defendant was not capable of criminal intent, or was unaware of the situation, they can still be convicted (e.g., of involuntary manslaughter), but the sentence probably won’t be as harsh.

There are four main types of mens rea: General intent, specific intent, motive, and knowledge/awareness. General intent refers to crimes in which there is no requirement for proof beyond a reasonable doubt about what was going on in the defendant’s mind. An example of a crime with general intent would be assault, as prosecutors only need to prove that the defendant intended to cause harm, but not kill the victim.

Specific intent crimes are those in which the prosecutor must prove that the defendant had a particular goal or end-game in mind when they committed the offense. A good example of a specific intent crime is burglary, as the prosecutor would need to prove that the defendant intended to commit theft or another felony inside of someone’s home. Without specific intent, the crime might be reduced to breaking and entering.

Motive refers to why a person committed a crime and is not necessary when proving mens rea. In other words, prosecutors don’t have to prove why you committed a crime, just that you did so knowingly and willingly. Still, establishing a motive does strengthen any claims of intent. Lastly, knowledge/awareness crimes are those in which the defendant must have known or been aware of the facts surrounding the commission of the offense. An example of this would be the possession of drugs with intent to distribute, as prosecutors would need to prove that the defendant was aware of what they were doing.

Concurrence (Mens Rea and Actus Reus)

Concurrence means proving both actus reus and mens rea at the time of the offense. This means that prosecutors must prove that you committed some sort of unlawful act (actus reus) while also having a “guilty” state of mind (mens rea). For example, for someone to be convicted of murder, prosecutors must prove that the defendant killed someone with malice aforethought (a.k.a., the intent to kill).

However, concurrence is not always necessary for a conviction. This happens when one of the elements of a crime is missing or can’t be proven. For example, if someone robs a bank, but it can’t be proven intended to do so, they may still be convicted for robbery (assuming all other elements are met).

Another relevant example of an exception is statutory rape: Statutory rape is a type of sexual offense in which the defendant is accused of having sex with someone below the age of consent.

Statutory rape does not require concurrence for someone to be convicted, because mens rea may or may not be there. Even if the defendant was unaware that the victim was underage, they might be found guilty. This makes statutory rape an exception to the rule and a strict liability crime.

Causation (Harm)

This crime element refers to the act’s connection with an injury, loss, or harm. For example, if someone walks into a coffee shop and shoots at another patron but misses, they can be charged with attempted murder because the shot was intentional (actus reus) and caused by their actions (causation).

However, if the defendant were provoked into a fight and killed the other person, they would not be guilty of murder because the death was not a result of planning. In this scenario, provocation is seen as an exception to causation.

The usual method for establishing causation is the but-for test.  This test asks the question, “but for the defendant’s actions, would the injury have occurred?” If the answer is no, then causation has been proven.

However, this test can be tricky to apply and isn’t always used in court rulings. For example, if two people are fighting and one person dies as a result of their injuries, it may be difficult to determine who caused the death. Using the “but for” test here wouldn’t yield clear results.

Proximate Cause: Proximate cause is another term used in criminal law that refers to the relationship between an act and injury. In other words, did your actions directly lead to someone getting hurt?

This element is important because it helps determine whether or not the defendant is responsible for the injury. For example, if someone hits someone with their car because they were texting and driving, their actions (i.e., texting) are seen as the proximate cause of the accident. This means that they are responsible for the injuries that occurred due to the accident.

However, if someone gets into a car accident because they were hit by another car, the other driver would be seen as the proximate cause of the accident and therefore responsible for the injuries that occurred. In this scenario, texting would not be seen as a cause for the damages, but it might be an extenuating circumstance for the person who hit them with their car.

In the same way, doctors are not held responsible for patients who die after receiving care, provided they did everything in their power to save them. Of course, there will always be exceptions (e.g., if a doctor makes an error that results in someone’s death), but as long as they meet the standard of care for their profession, they wouldn’t be liable.

Intervening cause: This term refers to an event taking place between the defendant’s actions and the injury, which breaks the chain of causation.

Say someone got hit by a car, resulting in a non-fatal concussion, only to die later because the trauma caused them to forget to take some life-saving medication. Failing to take the medication might be viewed as an intervening cause, because it was the actual cause of death. However, there’s no guarantee the judge or jury would view things this way, as it can be proven that the person with the concussion would not have otherwise forgotten to take their medication.

In other words, if you do something (dropping a match) that leads to another event (starting a fire), you are responsible for any injuries or losses resulting from that event. The intervening cause only breaks the chain of causation when it is unforeseeable, which means nothing could have been done to prevent it.

Independent sufficient causes: This exception to causation refers to cases where there are multiple causes for an injury. In these situations, the defendant will only be held responsible if they were a substantial cause of the injury.

In other words, if two different events lead to someone getting hurt, then you will only be held responsible if your actions were a substantial cause of their injury. If the other person would have been injured even without your actions, you won’t be held responsible for the damages caused by the entire event - only those caused by your own actions.

Additional Crime Elements

While the four crime elements explained above are part of nearly every crime (with a few exceptions), some crimes contain additional components. These are not required to prove a crime, but they can help explain why someone committed a specific crime and provide more evidence for the prosecution. Here is an overview of some of them:


An attempt is the first step in committing a crime. There are two ways for prosecutors to prove this element: 

  • through direct evidence, such as a written or verbal statement 
  • through circumstantial evidence, such as the defendant’s actions leading up to the crime

For someone to be convicted of attempted murder, for example, the prosecution would need to prove that the defendant took steps towards killing someone (e.g., purchased a gun or knife) and had the intent to kill. However, if it can only prove that the defendant had a gun or knife, but didn’t take any steps towards killing someone, they cannot be convicted of attempted murder.

So how does an attempt differ from a conspiracy? A conspiracy is when two or more people agree to commit a criminal act (e.g., murder). In this case, both parties are equally responsible for the crime even if only one of them carries out the act – unless one party is an informant for law enforcement.

To be convicted of conspiracy, prosecutors must prove that two or more people planned to commit some sort of criminal offense and took steps towards it. For example, in United States v. Shabani, the defendants were convicted of conspiracy to commit hostage-taking even though they never actually took any hostages. This was because they had planned to take hostages and purchased supplies, such as fake ID cards and weapons.

Attendant Circumstances

Attendant circumstances refer to the factual conditions surrounding a crime that further define it. For example, in a statutory rape case, age is an attendant circumstance, because it’s integral to defining the crime.

Extenuating Circumstances

Extenuating circumstances are facts that may lessen the defendant’s level of culpability, and thus their sentence and punishment. For example, if a person commits a crime out of necessity (duress), they may be found guilty but receive a lesser sentence than someone who committed the same crime without duress.

A good example is self-defense: Someone who was being threatened with physical harm can use self-defense as a justification for their actions, even if it results in the other person's death.


Punishment refers to what the defendant is sentenced to if they are found guilty of committing a crime. It is also sometimes regarded as an element of a crime, even though it’s not something the defendant does. This is because the punishment for a crime reflects the severity of that particular crime.

For example, someone who commits burglary (breaking and entering into a building with the intent to commit a felony) may receive a harsher punishment than someone who committed petty theft (taking something worth less than $500 without permission). This is because burglary is considered a more severe crime than petty theft.

In the United States, punishment is divided into four categories: Fines, community service, imprisonment, and capital punishment. Fines are used for less severe crimes; usually, those that involve compromising someone’s property or bodily integrity, but not death/physical harm. The same goes for community service: It’s a lesser punishment given to defendants without a criminal record, who are not considered a threat to society. It usually entails working for free in some sort of community organization, such as a homeless shelter or soup kitchen.

Imprisonment is used as the primary form of punishment for serious offenses. This involves putting the defendant in a carceral center of some kind (from a minimum-security institution to an administrative-maximum security penitentiary, i.e., supermax prison) to serve their sentence.

Finally, in 27 US states, the defendant can still be sentenced to death.

Final Thoughts

The elements of a crime can be somewhat confusing, but you can get a general understanding of them with a bit of digging. This will help you make sense of court rulings and criminal proceedings. While there are more than three elements that go into making up a crime, the three basic ones are mens rea (guilty state of mind), actus reus (the act itself), and concurrence (the two occurring at the same time). The final element, causation, is not always listed as essential.