The Riddler comes to NYC Marvel 616, and after getting a sense of how things operate, begins a string of crimes. These range from museum thefts, to the kidnapping and murder of corrupt high society socialites and politicians.
He leaves the usual kinds of clues, geared towards a Batman-level intellect.
Let's further assume Riddler at his best, as opposed to any jobber versions.
What happens? Which, if any, of the NYC Marvel street-levelers can stop him?