A special agent is a detective or criminal investigator who works for a government agency. He or she investigates suspected and alleged criminal violations of laws to determine if evidence is sufficient to warrant a prosecution. While other government agencies refer to their authorized representatives as agents, the title special agent is reserved for those whose general function is investigation, criminal justice and homeland security. However, not all criminal investigators are called special agents; some agencies entitle their investigators as criminal investigators although that term may have been used interchangeably with special agents. The term secret agent however, should not be confused with the special agent title, for while the latter is an individual employed in the capacity described above, the former is used to describe individuals employed or engaged in espionage. Special agents who are sometimes assigned to engage in secret or undercover activities as part of investigative operations and counter espionage might be referred to as undercover agents, but never as secret agents.