So Chris Darnell has been making large profits, memorialized by his own admissions and postings online....
26 U.S. Code § 6651 - Failure to pay tax
It is reasonable to expect that he has not been paying the appropriate taxes, not to mention bringing into question the issue of if the items sold were acquired legally.
Internal Revenue Service
Address: 1515 E Cedar Ave D-1, Flagstaff, AZ 86001
Phone:(928) 214-3303
It is pretty easy to initiate an investigation with just a phone call. Plus you can delete whatever you want from an online account, but it is never actually gone, and a quick subpoena can acquire all that is needed for an investigator.
CHEERS!