If you can't find the sender or 'firm' anywhere, the letter may be a bluff or scam. Paste it for an instant read.
Look up the sender, the firm, and the attorney. A real C&D comes from someone you can verify. No trace = strong bluff signal.
Don't pay or panic. Keep the letter, verify independently, and respond (or consult an attorney) only if it turns out to be a real, specific claim.
Yes — anyone can write one, which is why credibility depends on a verifiable sender and a specific claim. An anonymous one demanding money is often a bluff.