A locate message must be sent when?

A locate message is essential when another agency discovers a missing person. This communication serves to notify the original agency that the missing individual has been located, facilitating the process of closing the case and coordinating any necessary follow-up actions. When an agency identifies or comes into contact with an individual reported as missing, it triggers a need for confirmation and a formal update to the missing person's record, ensuring that all involved agencies are informed and can cease their active searches or inquiries.

In the context of the other options, sending a locate message is not necessary when information is incomplete, a person is reported missing, or simply when updating a record without a confirmed sighting or recovery of the individual. These situations may require different actions, such as gathering more information or initiating a search, rather than a locate message.