Ars Technica reports that hours before Keyes was sentenced, they received a letter (link) from an anonymous source, called “Sam Snow”, saying that Keys was wrongfully accused. In the letter, Snow described himself as someone who met Keys on a dating website in 2009. The pair dated briefly, but they eventually decided to just be friends. Eventually, Snow says, Keys gave him a key to his apartment, with an open invitation to come by anytime he wanted. Snow then describes how he did the actions Keys is accused of.
[Keys] never gave a username and password for any computer system to any hacker or hacking group. He never conspired to hack his former employer, and he never sent e-mails to any of his co-workers or the audience of the TV station where he worked. I know he did not do any of the things for which he has been accused—because I did them, and again this is something I can prove.
Keys tells Ars that he did not send the letter and declines further comment. Keys’ lawyers say that they had received a copy of the letter in January 2016 (it is dated January 3, 2015), but that it was far too late and contained far too little verifiable proof to be useful in Keys’ defense.