What is the appropriate professional response for a private investigator when approached by a reporter seeking details about an ongoing, confidential investigation?

1. Refer the reporter to the client or the client's legal counsel for comment.
2. Provide a brief, general statement about the nature of the case without revealing specific details.
3. Politely decline to comment, citing client confidentiality and professional ethics.
4. Share limited details that are already public knowledge to maintain transparency.