The newspaper photo of one of the killed doctors is of Paul Verhoeven, the director of the first Hollow Man movie. The photo was taken on location while filming Starship Troopers (1997), but has been altered for its use in this film.
The character's name "Michael Griffin" is a direct reference to the character of "Griffin" from H.G. Wells' 1897 serial novel "The Invisible Man". In Wells' story, Griffin was driven insane by his invisibility - much like the character in this movie.