Criminal Law

Aiding and Abetting a Crime

How the law treats those who assist, encourage, or instigate the commission of a crime.
By John McCurley, Attorney · University of San Francisco School of Law
Updated by Rebecca Pirius, Attorney · Mitchell Hamline School of Law
Updated: Dec 8th, 2023
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Obviously, someone who commits a crime, the “perpetrator,” is legally responsible for doing so. But can a person who merely assists the perpetrator also get in trouble? Yes. Anyone who aids or encourages the commission of a crime can face criminal consequences as an “aider and abettor.”



What Counts as Aiding and Abetting?

Aider and abettor laws vary by state. But generally, a person is an aider and abettor when he or she:

  • does or says something to aid, promote, or instigate the commission of a crime
  • with knowledge that the perpetrator is planning to commit a crime, and
  • with the intent to facilitate or encourage the crime.

Generally, just being present or having knowledge that a crime is being committed doesn’t amount to aiding and abetting. But, on the other hand, a person who aids or instigates a crime can be responsible as an aider and abettor without being there when the crime occurs.

And for a person to be guilty as an aider and abettor, the perpetrator must actually complete a crime.

Example: Robert plans to steal a six-pack of beer from the convenient store. He promises Boyd three beers for acting as a lookout. Boyd loves beer, so he agrees to help out with the heist. Boyd gets in position at the front of the store as Robert goes in to swipe the beer. Robert opens the freezer, looks at the six-pack, but ultimately, chickens out. Boyd isn’t guilty as an aider and abettor (though he did his part) because Robert never completed the theft.

How Is Aiding and Abetting Punished?

Aiding and abetting isn’t a crime itself—it’s theory of criminal culpability. In other words, someone who helps another person commit a crime won’t be charged with a crime called “aiding and abetting.” Instead, the person who assists with the crime will be charged, as an aider and abettor, with the offense the perpetrator actually commits.

Example: Billy Joe plans a robbery; he asks Bobbie Sue to be his getaway driver. Bobby Sue, with nothing better to do, agrees. The robbery goes well—that is, until Detective Mack picks up their trail. Detective Mack arrests Billy Joe and Bobbie Sue when they stop for gas just outside of El Paso. Billy Joe is guilty of robbery as the perpetrator. Bobbie Sue is also guilty of robbery, but as an aider and abettor.

Because the perpetrator and aider and abettor are convicted of the same offense, they generally face the same possible penalties. However, a judge will likely consider the extent of an aider and abettor’s involvement when deciding what sentence—within the allowable range—to impose. So an aider and abettor whose role in the crime was minor could end up with a lesser punishment than that of the main perpetrator.

Is an Aider and Abettor Responsible If the Crime Goes Wrong?

The crime that the aider and abettor and perpetrator plan to commit is called the “target offense.” But things don’t always go as planned. Oftentimes, a perpetrator will end up committing additional—sometimes more serious—crimes while doing or attempting the target offense.

An aider and abettor’s culpability isn’t necessarily limited to the target offense; aiders and abettors are also responsible for crimes the perpetrator commits that are a “natural and probable consequence” of the target offense. In other words, the aider and abettor is on the hook for the target crime and any other crimes that were reasonably foreseeable.

Example: Adrian plans a convenience store robbery. Bill agrees to supply Adrian with a loaded pistol in exchange for half the robbery proceeds. The robbery doesn’t go according to plan: The store clerk refuses to hand over the money and threatens to call the police. Adrian gets nervous and pulls the trigger. The clerk dies from the gunshot wound. As an aider and abettor, Bill is probably responsible for the robbery and killing—the robbery is the target offense and a jury is likely to find the killing was a foreseeable result of the robbery.

Is Being an Accessory to a Crime the Same as Aiding and Abetting?

An "accessory" is another common term used to refer to those who do something to help someone else commit a crime.

Many states’ laws distinguish between “accessories before the fact” and “accessories after the fact.” An example of being an accessory before the fact is acting as a lookout while another person robs a bank. An example of being an accessory after the fact is helping the robber hide and avoid arrest. Some states have only the crime of being an accessory after the fact and consider accessories before the fact to be aiders and abettors.

Accessories before the fact, much like aiders and abettors, are often charged and punished as if they had actually committed the offense. In other words, the perpetrator and the helper can be prosecuted, convicted, and punished in the same way. Accessories after the fact typically face less serious charges and receive lighter penalties than the perpetrator. These charges are separate crimes relating to obstructing justice or harboring a criminal.

About the Author

John McCurley Attorney · University of San Francisco School of Law

John McCurley started writing criminal law articles for Nolo as a freelancer in 2015. He joined the Nolo staff as a Legal Editor in 2016.  

Rebecca Pirius Attorney · Mitchell Hamline School of Law

Rebecca Pirius is a Legal Editor at Nolo with a focus on criminal law. She has worked in the area of criminal law since 2003, most recently as a senior policy specialist at the National Conference of State Legislatures (NCSL). For 12 years, Rebecca was a legislative analyst and an attorney in the Minnesota House of Representatives, providing nonpartisan legal research and drafting services to the 134 members. Right out of law school, she clerked for a judge in Minneapolis, Minnesota. Rebecca earned her J.D. from Mitchell Hamline School of Law in Minnesota, where she graduated magna cum laude and served as a law review member. She is a member of the Minnesota State Bar.

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