parents were spies. >> they really had assumed these notional identities, and that's who they were day in and day out. >> in fact, the murphys at home, you never heard them use russian. so they kept to their legend even when they thought they were by themselves. >> what is a legend? >> backstory. it's their persona, their identity, and everything that goes along with it, all of which is fake. >> legend building takes place over the course of years. >> russia has whole offices devoted to doing this. some of the identities are completely fictitious, like the murphys. in the case of the boston couple, heathfield, they are we call a dead double. someone identified a deceased canadian infant, and they sealed that identity and built an identity around it using original documents that they request from canadian authorities who don't know who they're sending them to.