You were a colleague of Hoffman's, but abruptly resigned to keep an eye on your brother, who was in a bad condition in the hospital because he was hit by a car.
You tried so hard to help him and the doctors tried, they promised you that he would live (they just blatantly lied to you) and when your brother died, you just couldn't find a place.
You found that freak who hit your brother with a car and you tortured him, he died painfully while you just watched him suffer and Hoffman watched from afar, but he did nothing. He understands you.
You never returned to work after that, sitting at home and not going anywhere, and Hoffman began to worry, but he was so busy working on your case (but only he knows that you are a murderer) and he simply refused to take it on, putting this case on hold, not wanting to frame you.