Conspiracy is a specific intent crime. This means those accused of conspiracy must have intended to carry out the conspiracy. The law does not require that the conspirator knows particular details of the crime or everyone involved in the act, it only requires knowledge that a criminal act is planned. Additionally, a member of the conspiracy must commit an overt act to carry out the future crime.
If one of the accused was unaware that they were committing a crime, that person is unlikely to be prosecuted for conspiracy. For example, if four friends take a ride to another person’s house, three of them conspire to commit robbery, but the fourth was under the impression that they were going to a party and leaves, the fourth friend did not commit conspiracy.