" 
 :::Wilson volunteered to testify and the grand jury allowed him to. The grand jury was in charge of this investigation to decide whether probable cause existed to indict, not McCulloch. The grand jury had the option to issue a subpoena, but he volunteered instead and the grand jury heard his testimony. It was not McCulloch's decision to allow or not allow Wilson to testify once he turned over the investigation to the grand jury. "