You know the story. The mob boss falls because someone from his organization gave information to the police. You might wonder: Does he have a right to find out the confidential informant's identity?
In a criminal case, the prosecution must disclose information that forms the basis of its case. This process is called discovery. A defendant is entitled to the names and statements of the witnesses that the prosecution plans to call, as well as a list of physical evidence and documents. The prosecution must also disclose any deal it has offered to a witness in exchange for testifying. While normally prosecutors have to disclose all witnesses who are relevant to the case whether or not those witnesses will testify, they often don't have to reveal the identity of confidential informants (CIs).
The government has an interest in not giving up the identity of a confidential informant to a defendant or anyone else. After all, a CI is someone who came to the police voluntarily and doesn't wish to be identified, often because of a fear of retaliation.
Courts have long recognized the importance of the confidential informant in solving crime. Police gain information and leads from these informants that they may not be able to learn from other sources. If police reveal the identity of an informant, they may not get any more information from that person, and others may be afraid to serve as informants. Given the importance of CIs, courts have granted them privilege, which means that they don't have to be disclosed in the same way as other witnesses.
The general rule is that the prosecution doesn't have to disclose the identity of a confidential informant. However, this rule has many exceptions; if a criminal defendant can show the importance of the CI's identity to the case, it may be possible to find out who's been talking to the cops.
After a defendant has made a motion to reveal the identity of a CI, the court will evaluate the circumstances and evidence in the case, and then make a call about how important knowing the identity of the informant is to the defendant's defense.
Factors the court will consider in deciding whether a confidential informer's identity should be revealed include:
The court may also evaluate the extent to which the confidential informant was involved with the crime. If the CI directly witnessed or participated in the criminal activity, then ordinarily the court will order disclosure. But if there is evidence of the crime from a source other than the CI, the court may decide to keep the informer's identity secret.
For example, say the police arrest Joe for embezzlement based on the information provided by a confidential informant, his accountant Ricky. Joe learns from the prosecution that the unnamed CI was involved in the embezzlement and is the main source of evidence for the prosecution. Joe argues that he needs to know the CI's identity. He claims that the documentation the CI provided the police is false, and that he needs the CI's identity in order to prove how it was falsified. Given that Ricky's information is material to the case against Joe, and that the basis for it is an essential part of Joe's defense, a court might grant a motion to disclose the CI's identity. But if Ricky was only one piece of the evidence against Joe, and the prosecution had other, independent evidence of Joe's criminal activities, then the court might decide it's not necessary to reveal Ricky's identity to Joe and his attorneys.
The prosecution and police typically don't have to reveal the identity of an informant if they don't have it. So if they get an anonymous phone call detailing some of Joe's shady business activities and use this information as a lead to uncover Joe's dealings, Joe would be out of luck at trial in discovering the identity of the person who ratted him out. The police are generally not required to conduct investigation to uncover the confidential informant's identity if it's unknown to them.
There are two opportunities to find out the identity of a confidential informant: before and during trial. If a defendant doesn't ask for disclosure of the identity at one of these two times, then the issue is waived (meaning that the defendant can't find out the identity later).
It can be an uphill battle to learn the identity of a confidential informant, but discovering it can also be crucial to a defendant's ability to mount an adequate defense. In addition, if a court orders disclosure and a witness refuses to name the confidential informant, then the court may strike the testimony of that witness or dismiss the case, so it's worth the effort to try and find out who the confidential informant is.