lee was married to a south african named juan geldenhuys with whom she had a son. although lee never spoke about her past, the couple had long suspected that savanna was not juan's biological daughter. what did the couple tell you about how they had discovered this secret? >> you know, i think it was a gradual process on their part. >> reporter: the couple told harris lee and her husband divorced in 2008 and that recently they themselves had had a falling out with her. more about their friend's mysterious past so they decided to do some investigating of their own. lee had once mentioned that she had a home in belize. armed with that, savanna's birth date and other tidbits of information they had picked up over the years, they searched the internet and discovered lee's secret. they're real detectives. >> i think so. >> reporter: they figured it out. they tracked you down. >> and then, essentially knowing the wrath that they would face if my ex-wife ever found out that they did it, they went ahead anyway. they told me, we feel like you have a right to know your daught