After witnessing Dexter kill Travis Marshall, Debra is shocked but helps him cover up the murder by setting fire to the crime scene. Meanwhile, Det. Mike Anderson is murdered by a member of the Ukrainian mafia, after finding a dead prostitute in his trunk. Dexter identifies him as Viktor Baskov and later kills him. Quinn and Batista begin to make amends as they investigate Anderson's and the prostitute's murders. Louis Greene hacks into Dexter's computer and cancels all his credit cards as the first phase of his agenda against Dexter. LaGuerta begins investigating a blood slide Dexter accidentally left at the church. Getting increasingly suspicious about Dexter, Debra ultimately ransacks his apartment and discovers his knives and blood slides, causing Dexter to admit to her that he is a serial killer.