Discovery is the process by which the prosecutor, court investigator, judge and defendant share information. The purpose of discovery is to eliminate "trial by surprise," increase efficiency in court proceedings by focusing the trial on the factual disputes between parties, and produce fairer and more accurate outcomes.
Opponents have argued that increased discovery provides the material and the incentive for defendants to custom tailor their testimony to the prosecution's evidence and would give defendants the opportunity to harass potential witnesses in advance of trial.
Discovery in Civil Law Systems
Discovery in the civil law systems is dramatically simplified in comparison to the hodgepodge of common law rules associated with common law jurisdictions such as the United States. In France, for instance, the defense attorney may review the entire "dossier" during several phases of the investigatory stage of the criminal justice proceedings. Although the exact rules on when a defendant can review the dossier varies in France depending on the court, the general rule is that the defense may review the entire file prior to trial.
Discovery in Common Law Systems
Prior to the 1930s, pre-trial discovery was rarely ordered by the courts and only came about by agreement of the prosecution and the criminal defense attorney. However, after the 1930s many states began to fashion discovery statutes which provided for compulsory discovery measures. These statutes, which borrowed heavily from civil law discovery procedures, provide for discovery from both the prosecution and the defense.
Originally discovery procedures were advocated by defense attorneys who argued that due process required some discovery because the prosecution had an unfair advantage in investigating, due to his access to police and other state resources. However, as discovery expanded, prosecutors began to argue that discovery should go both ways. Today there are discovery procedures that both sides must comply with and in some jurisdictions there is even Open File Discovery.
Depositions, long a staple of civil disputes in the common law system, are still rarely used in common law criminal justice systems. However, some states, such as Indiana, still permit both the defense and the prosecution to depose witnesses in advance of trial. All states retain depositions as a tool that may be used in order to preserve testimony of an individual who may not be available at trial.
Defendant's Discovery Obligations
In Williams v. Florida the United States Supreme Court upheld a statute which required defense attorneys to provide notice of an alibi defense upon written demand of the prosecution. The defendants had argued that the statute was unconstitutional because it violated the defendant's privilege against self-incrimination and foreclosed a legitimate defense if the defendant failed to comply with the discovery.
Following is a list of some of the types of discovery obligations that may exist in a common law system. It is important to note that exact discovery requirements vary from state to state.
- Alibi Notice- These provisions require the defendant to provide notice of an alibi defense prior to trial. Failure to disclose the defense may lead to the exclusion of witnesses who would testify in support of the alibi. If the statute fails to include a reciprocal discovery provision by the prosecution which requires the prosecutor to disclose his rebuttal witnesses, the statute may violate due process.
- Insanity Defense - Defense may be required to disclose their intention to use the insanity defense in advance of trial. After doing so, the defendant may be required to submit to a psychiatric evaluation.
Prosecution's Discovery Obligations
- Exculpatory Material- Due Proces requires that a prosecutor disclose material, exculpatory evidence that would either prove the defendant's innocence, mitigate the level of culpability, or otherwise favorably impact the defendant's case. In the United States, this material is sometimes called Brady Material
- Witness Lists - The prosecution may be required to disclose a list with the names and addresses of potential witnesses at trial.
Witness Statements - The prosecution may be required to disclose any written or recorded witness statements collected during its investigation.
- Defendant's Statements - In most jurisdictions the prosecution is required to disclose any statements by the defendant, written or oral, regardless of whether they are exculpatory in nature.
- Criminal Records - Prosecution may be required to disclose the defendant's own criminal record.
- Scientific Reports - Prosecution may be required to disclose scientific reports produced by experts, regardless of whether those reports are in fact going to be used at trial.
- Williams v. Florida, 399 U.S. 78 (1970)
- Wardius v. Oregon, 212 U.S. 470 (1974)