In tonight's episode, the private investigator was sure she had been hired by Visualize.  Why is that?  Perhaps that is because a known member of Visualize was the one who hired her!   Ray is a known member of Visualize now, and due to his absence towards the end of the episode, I find it highly likely he was the one murdering the private eye.  

On a side note, I think I solved another old mystery from season 1.  Remember in the episode "Red John's Friends", Jared Renfrew was found murdered and a message left in blood on the bathroom wall... "He is mar..."  I believe the message was meant to say "He is marked", this being a reference to the red tattoo on his left shoulder, as revealed by the private eye.  This leads me to think Red John has had this mark since season 1... maybe even years.  What is this mark?  Did he do it to himself, or was he branded by Visualize or someone else? I wonder what the significance is!