Frantic

Frank McGee is a boy in his freshman year in highschool and was adopted by a government official who has treated like his own .He has had a lot of questions about his real family but they have never been properly answered ,everyone simply tells him they died in a plane crash .He believes this until he starts getting a series of mysterious letters that say completely different .He is left puzzled ,who is the mysterious writer of the letters? Was what they were writing credible ?Had his family really died?