Marcus is the head of police, he personally has no "problem" with Monica. There are other people behind Monica's fall, but we don't know yet who they are. Marcus himself is just the executive force. As we know, Melanie gathered intel for Monica about Dick, so he really tried to help her and isn't behind this issue. Her husband embezzled money and was on the wrong side at the president's election. That seems to be the root of all problems. Also Steve is a player in this "chess game", but most likely not Monica's nemesis. There must be more powerful people somewhere in the shadows. I'm sure, we will learn about that piece by piece in the next versions.