At some of his kills and at Dexter's apartment, Brian left clues to his and Dexter's past.
She preferred the details to be out of focus.
He later snaps during dinner and destroys his father's awards as well as smashing Arthur's sister's , causing him to nearly kill Jonah by strangulation but he is saved by Dexter.
However, Manzon backs LaGuerta's version of the story, blaming the incident on Debra alone and thus betraying Debra's trust.
Running up serious debts, he pays them off by helping his kill others who cannot pay their debts.
At the beginning of season 4, Quinn is infuriated when Dexter botches a case he worked on.