Logan Ross is an unseen character mentioned in It Happened Last Night. Logan worked with Brody in Chicago for two years. Christopher LaSalle supposedly ran into Logan in the French Quarter and learnt about Brody's past from him. Brody was cornered by LaSalle and slowly revealed to him stories about her and Logan. At the end of the episode, LaSalle admitted Logan didn't tell him anything and Brody was caught. In an attempt to make it up, LaSalle told Brody he used to wear skirts because a girl he dated in college had a fetish for men in skirts. Brody halted his story and revealed that before coming to work, she in fact had breakfast with Logan who told her he ran in LaSalle and told him nothing. Brody told LaSalle all the stories over the past few days were bullshit and she exclaimed "Winner, Winner, Chicken Dinner."
Logan has not be revealed yet though he may be in future episodes.