Charlie Francis (Kirk Acevedo) was an FBI agent called in to investigate Flight 627 in the series pilot of "Fringe, " along with Agents Olivia Dunham (Anna Torv) and John Scott. (Mark Valley) He was a close friend of Olivia before and after she was promoted to the Fringe division.
Charlie did many favors for Olivia although he was never given any details about her work. He spent much of his time trying to help Olivia while also trying to figure out why she needed her unusual requests carried out.
Charlie was killed toward the beginning of season 2 by a shapeshifter from a parallel universe, who then took his form. Olivia was forced to kill the shapeshifter, which caused her much trauma, as it looked as if she had murdered her best friend.
"How are we supposed to protect people when corporations have higher security clearances than we do?"
"If we get caught, I don't know you at all."