Yes, it's the IRS. I had called a couple weeks ago since we still hadn't gotten our return (sent in February) and they said we would be receiving this letter but didn't say what they were auditing. I assumed it would just be my small business, which is no big deal, I keep detailed records. However, they sent Form 14815-A (Request for Supporting Docs to Prove the CTC) and form 886-H-DEP (Request for Supporting Docs for Dependents) and form 886-H-EIC (Request for Documents you need to claim EIC based on Qualifying Child). As for what the Letters are requesting, it's very specific. It needs their SSN cards AND their birth certificates AND proof of residency (that we all lived together) AND proof that my husband and I paid for things for them AND some type of documentation on official letterhead from like a school or court or something.
