Except that the OP did not post all the information to verify. The IP address does belong to the fbi.gov (both forward and reverse DNS lookups check out). The

Except that the OP did not post all the information to verify. The IP address does belong to the fbi.gov (both forward and reverse DNS lookups check out). The DKIM public key does exist at the given selector [0], but without the complete raw message, it is not possible to verify the signature. He also excluded the authentication-result header from his post. [0] https://www.mailhardener.com/tools/dkim-validator?domain=cjis._domainkey.fbi.gov https://www.mailhardener.com/tools/dkim-validator?domain=cji...