I was not able to find much.
I have acquired some documents on these cases, if anyone is interested, I can post an URL from where they can be downloaded.
But I think was key to his prosecution is that he charged for access, that made him personally liable. The Red Rose story site was also shut down and the owner prosecuted because she charged for access.
That is not strictly accurate. The two cases prior to Mr. Double / Thomas Arthur, were Karen "Red Rose" Fletcher and Frank Russell McCoy. All three ran their own websites; of those three, only McCoy did not charge for access. Now, it is worthy of note that both Fletcher and Arthur charged for access, albeit for different reasons. Fletcher charged for access to keep the materials out of the hands of minors, whereas Arthur made a business out of story distribution, and for some two decades, his website provided his sole source of income.
Both McCoy and Fletcher were charged with an offense under 18 USC 1462. Arthur was also charged under 18 USC 1466, which covers sales of obscene materials.
18 USC 1462 prohibits the publication of a link to where obscene materials may be found -- McCoy was convicted of this offense in 2013, and he served 18 months in prison for it.
What shields us is that although we have a website, we are not liable for content posted by our members.
Arthur was convicted for publishing four (4) stories, not authored by him, for which he received the maximum sentence of five years imprisonment per count, to be served consecutively -- 20 years in total. Both conviction and sentence on these counts were upheld on appeal. Arthur has filed a plea for certorari (cert) with the United States Supreme Court -- I believe he is appealing on the basis that the trial judge disqualified his only defense witness, and thus cut the legs out from under his defense. I am not at all certain if the Court will grant cert or not. If they fail to do so, the decision of the Appeal Court is final.
The Defendants Attorneys are listed here:
https://www.courtlistener.com/docket/16474654/parties/united-states-v-arthur/
He should have contacted the NCSF
I'm not convinced that this would have done him any good, to be honest.