He's apparently watching a street cleaner as he hoses down an alleyway, before Dexter Morgan approaches him from the shadows. He asks him if he can spare some change, to which the man moves closer saying "he's got something for him" reaching for a knife in his jacket. Before he can react, Dexter lurches forward grabbing the man with one hand and injecting him with M99 using the other.
Dexter proceeds to drag the body into a secluded area, behind some chainlinked fence. He pulls out from the man's other coat pocket a bloodied pink shoe with flower patterns on it, likely belonging to a girl this man had killed. Dexter stands overhead, pulling out his own knife and kills the man afterwards. It's revealed that he took a blood slide for this victim, as the next day he is seen depositing it into his box.