I use Wikipedia as a reference a lot. I know it's claim that you can not guaruntee anything there as thruth but thisis what it said about Phillip.
Sheppard was arguably best known for his bizarre behavior and erratic communication skills throughout the game. He continuously insisted that he was a former federal agent, but fellow participants such as former NFL player Steve Wright doubted Phillip’s claims.[6] At the finale, Jeff Probst spoke to a woman in the audience who claimed to have known Sheppard from her federal agent training to confirm beyond doubt that Sheppard was in fact a federal agent.[7]