Which of the following best describes the role of a documented confidential informant?

A documented confidential informant is best described as a source managed by agency guidelines. This means that their information and contributions are handled in a structured manner according to specific protocols established by the law enforcement agency they work with. These guidelines ensure that the informant’s identity is protected, their reliability is assessed, and their contributions to investigations are documented and managed appropriately.

By operating under agency guidelines, law enforcement can maintain the integrity of the informant's information while protecting both the informant’s safety and the investigation's effectiveness. This structured approach allows agencies to utilize informants effectively, ensuring that they are credible and that the information provided is actionable.

The other options do not adequately capture the nature of a documented confidential informant. For instance, a source that is never shared may indicate complete secrecy but does not imply active management or utilization in investigations. A casual informant suggests a more informal relationship without the structured oversight that characterizes a documented informant. A source of public information contradicts the very concept of confidentiality, as a key aspect of a confidential informant is the protection of their identity and the sensitive nature of their information.