>> 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.thst wasounl by u.s. postal service inspectors. >> justin herdman: this is essentially enough fentanyl and carfentanyl to kill every man, woman and child in the city of cleveland. >> pelley: just this? >> herdman: just this. >> pelley: carfentanyl is a derivative used by veterinarians to tranquilize elephants. >> herdman: carfentanyl is another 100 times more potent than fentanyl. here, you've got 300 grams of powder that could ve fatal dose to 150,000 people. here, you've got only five gram