This is interesting: https://www.yahoo.com/news/fingernails-spotted-trash-led-arrest-alleged-killer-071132962.html "Each and every murder in this case could have been done by a mystery man with a mystery gun with mystery DNA," Amster said."
Reminds me of the "Plan B" defense from "The Practice." Of course the DA would respond to the defense with scorn. That's a DA's job- to present a case against the accused and to make the defense look weak in comparison. If the client insists on pleading not guilty, the defense attorney has the responsibility of putting forth the best defense under his or her abilities, even in the face of his or her client's seemingly obvious guilt. That's the defense's job. I'd agree that it's and interesting case to follow, but hardly anything apart from the norm. If they have the right guy, and it certainly looks like they do, what he did is too horrible for any amount of punishment to make up for. At least this process will put him where he can't do any further harm.
I predict that his defense will work about as well as Fatal Vision centerpiece Jeffrey MacDonald's did when he blamed his family's murders on hippies, chanting "Acid is groovy!"