I think libel is correct. I was referring to the letter sent to Feinstein. And, yes, the statute of limitation is long past, you are correct.
"Slander involves the oral "publication" of a defamatory remark that is heard by another, which injures the subject's reputation or character. Slander can occur through the use of a hand gesture or verbal communication that is not recorded. Libel, on the other hand, is the written "publication" of a defamatory remark that has the tendency to injure another's reputation or character. Libel also includes a publication on radio, audio or video."