About an hour before sunrise on a mid-January morning in 2019, two FBI agents arrived at the home of Fidel Marquez’s mother, where the longtime executive of Commonwealth Edison had been staying.The agents played a series of recordings of wiretapped phone calls for Marquez, featuring Marquez himself. When other people in the house began waking up, the agents took him to a nearby strip mall parking lot to continue talking.Over the course of two hours, the agents laid out the government’s theory that Marquez and …