Final answer:
The authorized agency may make a written request to the insurer at the beginning of the investigation, after gathering evidence, or before conducting interviews.
Step-by-step explanation:
The authorized agency in an insurance fraud investigation makes a written request to the insurer at different stages of the investigation depending on the circumstances. It is common for the authorized agency to make a written request at the beginning of the investigation to inform the insurer about the case and gather necessary information. However, they may also make written requests after gathering evidence to provide updates or request additional information, and before conducting interviews to seek permission or inform the insurer about the upcoming interviews.