Continuity mistake: The clock in the hotel initially reads 9:21 and then abruptly changes to 9:20. (00:19:48)
Continuity mistake: When Keen enters Red's Bethesda apartment, the camera pans over pictures on the mantel. Directly left of the picture of a little girl/man on a swing, is a picture of a woman holding hands with 2 children (looks like 1980's, adult woman looks like Keen.) When Keen reaches out to pickup/view the swing picture, the woman/children picture is no longer there and a really old family photo is in its place. (00:21:25)
Answer: The man Red killed, Sam Scott, was Lizzie's adoptive father, not her biological one. However, at that time Lizzie (and thus the audience), was led to believe her real father abandoned her and her mother, so expect more secrets to be revealed how her real father actually died (or if he's even actually dead).
Bishop73