Because of the "statute of limitations" in the USA, any prosecution of this individual for interfering with an investigation in 1967 would fail. But that wouldn't apply in 2016 if it was found that he didn't author the three Bates letters. An open investigation of an unsolved murder being interfered with by somebody claiming to have authored three malicious communications, when they didn't author them, could be argued, is a criminal offence subject to prosecution. Any reasonable investigation into this individual that concluded he wasn't involved in the murder of Cheri Jo Bates, should have been achieved through proper evidence lines.
From the "word salad" presented by the Riverside Police Homicide Cold Case Unit, without any meaningful explanation to their findings, one can only conclude that the above statement is not the truth. This individual identified claimed to have written the three Bates letters but failed to admit he typed the Confession letter and authored the Riverside Desktop Poem. And if he didn't claim all three, then he likely didn't author any. An individual claiming to be "remorseful for their actions" in 1967 by sending another anonymous letter in 2016 and further muddying the waters, should be viewed as less than honest.