Chet Peterson is an unseen character in Far Cry 4. The first and only time he appears in game is through a phone call that Ajay Ghale, the game's lead character, remembers during the opening cutscene at the beginning of the game. Chet states that he is part of the American embassy in Patna, India, and during the call, mentions that he could not find any evidence of Ajay's Kyrati citizenship(which suggests that he did not know his date of birth or his aristocratic family) and that Chet is bound by law to warn Ajay of the dangers of his trip into Kyrat, because "due to the civil unrest" the United States has no "diplomatic presence" in Kyrat.
"Uh, Mr., Mr. Ghale, this is Chet Peterson from the U.S. embassy here in Patna. I--uh--I'm calling you pursuant to the application for a tourist visa for India with further travel to Kyrat. We can only accept your status as a U.S. citizen as we have no official records regarding your Kyrati citizenship. Furthermore, I must legally advise you against traveling into Kyrat. We have no official diplomatic presence in Kyrat due to the civil unrest with the Golden Path. In regards to your intent to bring with you the cremated remains of one 'Ishwari Ghale', you will need to bring with you the passport for the deceased..."