What action signifies that an investigator can resume standard duties during a casualty?

When an investigator is relieved by the fire or repair party, it signifies that the immediate threat has been addressed, and it is safe for the investigator to resume standard duties. The fire or repair party is specifically trained to handle hazardous situations and, upon their arrival and subsequent relief of the investigator, indicates that they are now taking responsibility for the area. This allows the investigator to step back from the crisis management role and return to routine tasks.

Receiving acknowledgment from command, while important for communication and protocol, does not directly indicate that the area is safe or that the duty of handling the situation has transitioned. Similarly, a report of the area being clear might not involve an actual change in personnel or readiness to return to normal duties; it merely indicates the situation's status. Finally, securing all firefighting gear is an important procedure following a crisis but does not determine the investigator's readiness to resume standard duties.