Rosalind Harker

In the episode titled "Red John's Footsteps," season 1 episode 23, Red John knew that the CBI would trace the airplane and smiley face in the sky back to the suite 21 mailbox. I think Rosalind purposely put that letter to Roy to lead Patrick right to her. This way, she could tell Patrick whatever she wanted; she could manipulate him. Patrick would never question anything the blind girl has to say. I believe Roy Taglifero and his entire situation is completely made up by Rosalind.

In the same episode, Rosalind pours a cup of tea for Patrick and Lisbon. In the end of the episode, the same cup (with the same design) was still steaming in front of the television where Red John was watching Patrick.

Rosalind plays classical music, just like Patrick's daughter does in almost every flashback Patrick has.

She also has a smiley face on her wall from Red John. She knows Patrick will see it when she lets him into her room, but also knows Patrick will not ask her about it.

Lastly, every time Patrick gets close to finding Red John, Rosiland somehow shows up.