Conspiracy is generally described as a criminal partnership wherein two or more persons agree to commit one or more crimes. While conspiracy is a crime to do something unlawful; the crime agreed upon does not have to be committed.
A formal agreement among the conspirators is not necessary to prove that a conspiracy took place. Nor must the conspirators have agreed on each detail of the conspiracy. Merely meeting, discussing every day matters, acting in similar ways, or even assisting one another is insufficient to prove conspiracy. It must be shown that a plan to commit at least one of the crimes alleged in the indictment as an object of the conspiracy with all of the defendants agreeing as to the crime which they agreed to commit.
An individual becomes a conspirator by willfully participating in the illegal scheme with the intent to advance or further some object or purpose of the conspiracy. This is true even if the individual does not possess full knowledge of all the details of the conspiracy. Additionally, one who willfully participates in an existing conspiracy is as guilty as the original conspirators. However, one who posses no knowledge of a conspiracy, but happens to behave in a way which furthers some object or purpose of the conspiracy, does not become a conspirator. Also, a person does not become a conspirator simply by associating with one or more persons who are conspirators, nor merely by knowing that a conspiracy exists.
An overt act in and of it itself does not have to be unlawful. A lawful act may be an element of a conspiracy if it was done for the purpose of carrying out the conspiracy. The government is not required to prove that the defendant personally did one of the overt acts. The government must prove beyond reasonable doubt that (1) there was an agreement among two or more people to violate a federal drug law, (2) knowledge of the the scheme and an intent to join it, and (3) voluntary participation in the alleged conspiracy (United States v. Turner, 319 F.3d 716 (5th Cir. 2003)). The statute is very broad and allows proof based on circumstantial evidence of an illicit association. (Id.)