mcfadden has the details reporter: edward peng is in custody tonight, a naturalized american citizen, who worked as a tour guide in san francisco, despite receiving a degree in mechanical engineering in china. the chinese are the number one intelligence threat to the united states right now. reporter: no question? no question the russians are up there for sure but the chinese are number one and also the number one threat in the political espinoage context. reporter: the criminal complaint unsealed today reads like a spy thriller, complete with dead drops and code words beginning in march of 2015 when the fbi launched an elaborate sting operation, planting a double agent inside a ring of chinese intelligence operatives in china to string the chinese along, the u.s. double agent filled sd cards with non-harmful secrets carefully curated by the u.s. government from today s complaint, put the sd card in a book, wrap it in a bag, mark the package to ed and leave it at the front