There was a rumor that the stories in Rizzoli & Isles season 4 were going to dive into darker territory.
"Dance With the Devil" definitely took things to such a place.
I always knew Paddy Doyle was a criminal. He was up on RICO charges and accused of being behind the murders of at least 15 people. Yet being Maura's biological father, the man who had always tried to protect her, seemed to humanize him.
That disappeared with this episode.