i'm ssa jim gaylord.upervise the southern intelligence squad in southern californi we were called to headquarters. they didn't tell us what it was about. before we could be exposed to the information we were given about this case, we had to be polygraphed. that's never happened to me before. so i knew the information itself was very sensitive, so they were taking extra steps. steps that i'd never had to take before. >> where did the information come from? >> i can't actually tell you how we got the information. i'm not trying to be coy, but we also have to protect our sources. we sat down and we were told that china was stealing u.s. naval secrets. kevin moberly is one of the first three agents we had on this case. >> it was around 2003 that i joined the fbi, and immediately upon arriving to the squad it was evident our number one threat was china. >> the fbi is calling for your help in identifying chinese spies amid growing evidence that china is now this nation's greatest intelligence threat. >> china i