Columbo? Love it!Here's what I imagine is happening: the police know who did it, but they are taking their time, collecting all the evidence, building a case, and they are waiting for their POI to make an incriminating move or statement.
I imagine the Midlothian PD has an old, rain-coat-wearing detective with a glass eye, driving an old beat-up Peugeot Cabriolet, who is continually making contact with the POI to gather all the facts. And he always has, "Just one more question...."