So I thought someone should collect all the Red John evidence from the six seasons and post it for everyone to see. Please comment below if you have further important evidence to add.

Rosalind Harker's description:  Under six feet.  Not thin but not muscular.  Straight hair.  Strong hands.  Soft voice.  Enjoyed Bach.  Smelled of pine and earth and nails.

Jared Renfrew:  He claimed Red John was a friend of a friend.  He had once won the Heisman Trophy.  When Renfrew was dying, he wrote on the bathroom wall He Is Mar...

Kristina Frye:  She was hypnotized by Red John into thinking she was dead.  Quite a mental feat.

Lorelei: She says PJ and RJ are just alike.  "I wonder why the two of you didn't become lifelong friends the moment you shook hands."

William Blake:  He quotes the poem to Patrick.  "Tiger, tiger, burning bright.  In the forests of the night.  What immortal hand or eye could frame thy fearful symmetry?"

Sophie Miller:  She describes RJ as a charming man, but with a dark cloud around him.  He was middle-aged, in good health, had no living family but many friends upon which he relied for comfort and support.  She believed he had a real phobia, not necessarily acraphobia, but something else perhaps.  He appeared calm and collective in the waiting room, though I note he is an excellent whistler.

The Red Barn:  Murders were committed at a Visualize farm by Red John in 1988.  His smiley face appears on the Barn outside. Most likely his first kills.

Kira Tinsley:  She was a P.I.  She claimed she was hired by Visualize to bug the CBI office and get close to Cho.  She is later killed and uses her last breath to tell Patrick her attacker has a tattoo, three dots on his left shoulder.  

Okay RJ hunters.  Use this information wisely!