Suppose three people named Adam, Brian, and Charlie decide to rob a bank. They devise a plan in which Adam is going to go in first and announce that a robbery is occurring. The plan is for him to take out a gun and to scare everyone into submission. While he does this, Brian is supposed to go into the vault and take out all the money. Charlie is waiting outside in a car with the engine running. After Brian takes out all the money, he and Adam are supposed to run into the car and Charlie is supposed to drive off. Suppose this happens exactly according to plan. However, Adam leaves behind his ski mask which has his DNA on it. Adam is then arrested. In an effort to avoid jail time, Adam agrees to reveal the identity of Brian and Charlie and to testify against them. To what extent are Brian and Charlie guilty of the robbery? In other words, suppose they are each indicted for one count of Robbery in the First Degree. Pursuant to New York law, a person is guilty of Robbery in the First Degree when he forcibly steals property and he uses a firearm in the commission of the crime. Here, the only person who was armed with the firearm was Adam and he cut a deal with the government. Are Brian and Charlie also on the hook for the robbery? The answer is yes.
Like in most jurisdictions, New York law has an accessorial liability provision. Accessorial liability, also known as “acting in concert” occurs when the acts of one person are imputed to another. So in the hypothetical listed above, all three individuals are guilty of first degree robbery even though Adam is the only one who was armed with a firearm and who actually used force. In New York, the acts of one person are imputed to another whenever two things happen. First, the person has the same mental state as the person who commits the act. Second, the person “solicits, requests, commands, importunes, or intentionally aids” the other in his criminal act. So even though Charlie didn’t commit any of the elements necessary for him to be convicted of the robbery, he had the same mental state as Adam (to rob the bank) and he intentionally aided Adam in that he agreed to help him get away with it by being the getaway driver. The same is true for Brian in that he also had the same mental state to rob the bank and he aided by being the bag man. So anytime you have the same mental state as the actor and you help out in some way, you are guilty of the same crime even though you didn’t necessarily “commit it.”
This is an easy enough principle to understand. The reason it gets tricky though is because mere presence is not a crime. In other words, pursuant New York law, a person is not guilty of a crime simply because he knows that a crime is taking place. Nor is he guilty for being at the scene of the crime (this does however conflict with other portions of the law particularly in situations in which a person is in a room with contraband in plain view). For him to be found guilty, the prosecutor must prove the elements for accessorial liability. As I stated, this can be factually complicated, but that’s how the law works.