There are three critical elements for any crime. The act itself, which we sometimes refer to as the actus reus, the mental state involved, which we sometimes call mens rea, and the concurrence of both the physical act and the mental state. Did a person with an evil mind use an evil hand to commit a wrong? That's how at least one judge has phrased it. With the wrong act and with a mental state to commit a wrong happening at the same time, we have a crime. Mens Rea is Latin for a guilty mind. It refers to what's going on in a person's head at the time that he commits a crime. We in general do not have a strict liability standard for crime. In other words, you can't accidentally or unintentionally or unknowingly commit a crime. You must commit a crime with a knowing heart and mind. We can trace this back to Morissette versus United States where a junk dealer collected spent casings from a military yard and later recycled and sold those casings for a modest profit. When the government charged Morissette with embezzlement, he protested that he never meant to steal anything, that he thought the casings were abandoned and that he had no ill intent. Nevertheless, the jury convicted Morissette and the case was appealed all the way to the United States Supreme Court. In overturning Morse's conviction, the court said one could not accidentally violate the law, and that there was no such thing. Generally speaking, as strict liability in the criminal law. If a person such as Morissette was actually ignorant of committing the crime, then no crime has occurred. Another way of thinking about strict liability is that, in general, in American law, the circumstances matter. Your acts matter, and your state of mind matters. Let's use the example of a construction site and someone operating a crane. If that person operates the crane in a way that harms another individual. There are a number of ways that a prosecutor could think about the harm inflicted if there is, um, the ultimate bodily harm inflicted and a victim dies because of the operation of the crane. The prosecutor could charge the crane operator with murder. Another option is that the prosecutor could charge the crane operator with manslaughter for an unintentional killing. Another possibility is that the prosecutor could decide not to charge the crane operator at all because he had no ill intent. A fourth option outside the criminal system is that the victim's family may sue for civil damages beyond what the government elects to do. So there are at least four possibilities for how such an accident could be handled in the eyes of the law.