Defense Investigation

Unlike civil cases, where much of the litigation process is devoted to pretrial discovery, pretrial discovery is an extremely small and limited part of a criminal case.  In most cases, the defense will file a standard "Motion for Discovery," requiring that the prosecutor produce all information and documents relating to the case that would be discoverable, including any information that may tend to prove the accused's innocence.

Beyond that, there are no depositions, interrogatories, requests for admission of facts or similar tools available to criminal defendants as there are in civil cases.  There are also substantial restrictions on a defendant's right to pretrial discovery which are designed to protect the identity of government informants and to prevent intimidation of witnesses.  But, even though a defendant's pretrial discovery is limited, the discovery process in a criminal case is largely a one-way street.  Having had the benefit of grand jury inquisitions that excluded the defense, prosecutors may not ordinarily obtain pretrial discovery from the defense.

Prosecutorial Grants of Immunity

While the prosecution cannot obtain discovery from the defense, prosecutors may take full advantage of the subpoena power of the grand jury to uncover important evidence on which to frame criminal charges.  However, in many cases, particularly more complex matters involving criminal conspiracies, corruption or organized crime, prosecutors face significant challenges in compiling evidence against the leaders of various criminal enterprises.  Beyond fear of retribution, those who have witnessed a pattern of criminal activity may assert their Fifth Amendment privilege against self-incrimination and refuse to testify about any crimes in which they were involved.  Where necessary, prosecutors may avoid this obstacle by granting these witnesses "immunity" from prosecution.  Because their testimony may not be used to incriminate them in later proceedings, such grants of immunity eliminate the need to "take the Fifth" and avoid prosecutor's questions.  If certain witnesses remain uncooperative, the prosecutor may move to compel these witnesses to testify.  In general, there are two types of immunity.  If the prosecution affords a witness what is known as "transactional immunity," it may not prosecute the witness for any crime arising out of the occurrence to which the witness will testify.  Because this is an extremely broad form of immunization, prosecutors ordinarily grant a more narrow form of protection, known as" use immunity."  Where a witness is promised use immunity, the government may not use the witness' testimony, or any information derived from that testimony, to prosecute the person later on.  If the prosecution can prove its case without such information, it is still free to prosecute the witness on the basis of other evidence, but must prove that it was not, in any respect, derived from the immunized testimony.

By selectively offering immunity to key witnesses, prosecutors may not only compel these persons to testify before a grand jury, they may similarly force these witnesses to testify at a later trial, where defense counsel will undoubtedly seek to impeach their credibility by emphasizing the fact that they are testifying under a grant of immunity.