If they had DW's name/address or phone number from a CHILD PORN RING website proving he downloaded the porn from there, THEY WOULD HAVE HAD IT IN COURT.
If he was on a mailing list, THEY WOULD HAVE HAD IT IN COURT.
IF they had videos/images with DW having sex with a child, THEY WOULD HAVE HAD IT IN COURT.
Is there some other 'way' you have that he could be connected with a CHILD PORN ring? That wouldn't be admissible in court?
It may also be the DA's intention to file charges for teh ring if he gets off of the existing charge.
But all of this is speculation.