I have always been certain it is Patrick Jane.

I believe that big clue Heller talks about from this episode is the fact Jane touched Van Pelts shoulder. He clearly has her under a state of hypnosis. If you watch the episode again, when Jane rings Lisbon upon her entering the house, and he asks where are you? there is a smile.

he told her to tell no one under the assumption that she would tell her team, thus jane can then use this to his advantage

All 7 suspects are probably accomplices or know something and he is wanting to clear the evidence by killing them off one by one.. 

Watch the clues, its there.. The whole show is based on look at the clues and the truth is staring at you.