I see that, amid all this flaming and BS, your question wasn't answered:

If you are an accessory to a crime, you are charged with the same crime as the principal perp. For example, if I'm a bank robber and I hired you to drive the getaway car, and we were caught, you'd be charged with bank robbery, too, because you "aided and abetted" me in robbing the bank. You can't get off simply because you weren't inside the bank with me. The prosecutor will contend that I couldn't have robbed the bank without your help. Another purpose of "accessory" charge: The prosecutor needs you as a witness against me. So, he'll tell you that if you agree to waive your Fifth Amendment privilege and answer all questions about the robbery truthfully, you won't be prosecuted as an accessory--you'll walk.

A conspiracy rap is a tool that prosecutors use to gain an easy conviction of a hard-to-get perp. Two reasons: first, the prosecutor doesn't have to prove Patriarca actually committed a murder, only that he was "conspiring" with others to commit a murder. Second, the judge will allow "uncorroborated testimony from unindicted co-conspirators." That means that if you were a "little fish" in Patriarca's family, and you were part of the "conspiracy" (i.e., Patriarca discussed the murder in your hearing), the prosecutor will call you in, tell you that you are a "co-conspirator"--then promise that you won't be indicted if you agree to testify against Patriarca. And, if you do, the prosecutor won't have to produce a "corroborating witness"--someone else who heard Partriarca discuss the murder with you and who's willing to testify. Corroborating witnesses are usually required to press felony charges in cases other than "conspiracies."