There's suspicious activity. Activity that someone probably told Rudolph was connected. That's why there's an investigation instead of an arrest warrant.
Then there would be a homicide investigation carried out by homicide investigators since Murphy hasn't been on the police force for years now, and Harry the same, they are private citizens. It shouldn't be Internal Affairs, when asked the question, Bradley guesses, "because Murphy and Harry used to be?"
Which strikes Murphy as very odd indeed.
She says page48 of Peace Talks;
"Because I was one of theirs,he guesses,"Murphy said. "Bradley doesn't guess about anything. He doesn't know why IA has the case."
I rubbed at the spot between my eyes and growled. "Someone is pulling strings behind the scenes. They got the case bumped over to one of their people. Rudolph."
"And Marcone owns Rudolph," Karrin said. She pursed her lips. "Or so we assumed."
"Who else would have him? Who else has so much influence in this town?"
By the end of the chapter, Harry wants to find out who else might be pushing Rudolph, he wants the Paranet to look into it. As my dear old dad used to say, you stir a pile of crap long and hard enough it will begin to smell, Bradley is good at that, though otherwise he is a decent cop.
This sounds like a set up for blackmail at some point down the road. If they had straight forward evidence to give them cause, it would be a homicide investigation handled by homicide investigators. Not an in house IA investigation where one of the investigators doesn't even know why it is them looking into it. No, it is someone who wants very badly to get something to hold over Harry and Murphy's head. My five cents goes on Nic, this whole caper backfired on him badly.. He wants the Spear of Destiny, he figures Harry has it. I bet if not by the end of this book, then in the next one or so, he will show up demanding Harry turn it over to him or he will see him or Murphy, or both arrested for murder one, assuming she survives.. We know what happened when Mavra tried that one. But that is the only way this chapter makes any sense, and I still think it is possible that because of what went down in front of Mab, Marcone would like to see Harry sweat a bit.. But at this point in Peace Talks, he has no clue of what is about to happen, otherwise he'd have forgotten the whole idea.
It also fits with Murphy not being there at Christmas, she has taken the fall and is in prison thanks to Nic.