If DPR is (and always was) Ulbricht then I think we would know by now if he was Satoshi.

LE have Ulbrichts computer and most likely access to all his online accounts. Given Ulbrichts track record of data security, they'll probably have access to all his e-mails and files from the past 5 years at least (after all, he did get caught.)

I think if anyone would leap at the opportunity to prove beyond reasonable suspicion that Bitcoin was made by a criminal to buy and sell drugs, it would be LE.