A process works better than a job title. State the question, why it matters, who the audience is, the scope, and which kinds of sources are acceptable. Then specify the output format, such as a one-page brief with a short summary first.
Ask it to plan first by listing sub-questions, then gather evidence, then synthesise. Tell it to separate facts, inferences and unknowns, and to say "not found" instead of guessing. Use a tool with web search, or paste in your own documents, so it works from real material. Ask for links or page references. Open the key sources and check them yourself, because AI can invent citations that look convincing.