Even if a person does not actually commit a crime, they can be charged with the “attempt” to commit the crime.
Elements of the Crime
A person is guilty of an “attempt” to commit a crime if (1) he has intent to commit a crime, and (2) he engages in conduct that strongly supports any evidence that the he intended to commit the crime.
For example, law enforcement receives a tip that John Doe is planning on robbing a bank. Police investigate and find that John Doe recently purchased a mask, an assault rifle, and a large duffle bag. Police arrest John Doe on charges of attempted robbery. The State will argue at John’s trial that his acts in purchasing the mask, assault rifle, and large duffle bag were all acts corroborating his intent to rob the bank.