>> cronin: at least. >> pelley: and all of these came from where? >> cronin: it was universally china. >> pelley: what did you do next? >> cronin: instead of trying to find our way to a target, we had far too many. so what we decided to do was go through the list and see any that popped out. and one name in particular struck out, out of the list. >> pelley: what was that name? >> cronin: gordon jin. >> pelley: when gordon jin was making claims about what he could provide, what did he tell your undercover agents? >> cronin: what gordon jin said he could provide to you was essentially, any drug you could imagine: those that exist, those that don't even currently exist. he called it custom synthesis. what it really meant was made- to-order poison. >> pelley: we'll track down the man prosecutors say is gordon jin, in a moment. but first, have a look at fentanyl and its derivatives. justin herdman is u.s. attorney in cleveland. he told us some of this was seized by the d.e.a. the rest was found in the mail by u.s. postal service inspectors. >> justin her