Hi there,
I was just thinking about the possibility of Red John's return;

One part of my belief that Red John will return was the titles of the episodes:
for all five forst seasons, most of the titles of the episode had "red" in their names, or a reference to the color (blood, strawberry, cherry, blush for example). 
As i'm french and i used to be looking to the episodes in french with a translation that did not include those references most of the time I did not pay attention to this before.

If you want to check, here is the list of the titles of the episodes from s1.
http://en.wikipedia.org/wiki/List_of_The_Mentalist_episodes


Since the "end" of red john, whiwh is supposed to be a fresh start for jane yet the titles of the episodes have kept references to colors in their names, every color except the red one, of course :

9-My Blue Heaven
10- Green Thumb
11- White Lines
12- The Golden Hammer
13-Black Helicopters
14-Grey Water 
15-White as the Driven Snow
16-Violets
17-Silver Wings of Time 
18-Forest Green 
19-Brown Eyed Girls
20- Il Tavolo Bianco (the white table)

I don't really know how to understand this but it can't be a coincidence or routine. We are all expecting the red name to appear in the last episode aren't we ?
 

I accuse Patrick Jane to knowingly arresting the wrong suspect as the killer in the last episode Black Helicopters.

What leads me to this conclusion is the following:

1.) His speech to the "leader" Alex before he adresses the group:

"Alex. I like what you're doing here, and I want to help you. Will you let me
speak to them now? I'm gonna say something that may shock you, but if you work with me, I guarantee you will come out of this a big hero. You will be golden. I promise. Yes?"

2. ) Alex behavoir during Janes "thing"

After that speech he assembles all suspect over 45.  Alex is the only one shown in a ray of light.

Jane is walking back and forth.

"Edith Firlock knew a lot of radical fringe types from the old days. One of those old friends... is on the run"

As he delivers his first punchline he looks strait into Alex' eyes.

[IMG]http://i61.tinypic.com/3520is0.jpg[/IMG]

he turns and continues: "...and using your farm to hide out" as he delivers this second part Alex bows his head in shame.

[IMG]http://i60.tinypic.com/168e9hc.jpg[/IMG]

Jane walks back toward the other side.

"Now, I think Edith figured that out and came down to pay a visit."

"Any takers?"

As Jane asks that question he again looks strait into Alex' eyes. After a moments hesitation Alex turns his head to break eye contact and evade the glance.

[url=http://postimg.org/image/pl1xpfw0t/][img]http://s30.postimg.org/pl1xpfw0t/vlcsnap_00075.jpg[/img][/u................]

As Jane gets arid of all none gun owners the camera first shows Alex looking down and then again his head in the light as the others leave.

"The killer's starting to get nervous. The killer feels like
it's 110 degrees in here."

As he plants that suggestion Alex wipes sweat of his forehead. Jane eliminates the two people to the left and right of Alex.

The look of despair is quite apparent on his face:

[url=http://postimg.org/image/nco7rh5ul/][img]http://s30.postimg.org/nco7rh5ul/vlcsnap_00078.jpg[/img][/u...........]

Patrick is continuing planting suggestions:

"And I would suggest that the killer can now see Edith... Every time they blink.Yeah. You can see her, right? Coming for revenge. Right in the corner of your vision."

As Jane is finishing the last sentence Alex is pushing his shirt to the side ready to draw his gun. While the other 3 suspects are listening with expression ranging from sleepy, bored to annoyed Alex face and body display extreme tension.

[url=http://postimg.org/image/b7qo8q865/][img]http://s22.postimg.org/b7qo8q865/vlcsnap_00080.jpg[/img][/u......]

 Jane finishes the speech by saying:
"That poor woman."

He again faces Alex and stares strait into his eyes with nothing but a few inches between them.

[url=http://postimg.org/image/c3a8s1fbx/][img]http://s30.postimg.org/c3a8s1fbx/vlcsnap_00079.jpg[/img][/u.....]

Just before Alex was about to break Marsha steps in to take the blame. Soon after she drew her weapon she starts crying looking at Alex.

Earlier this episode Jane said:

"Well, knowing what people secretly want is what I do."

Jane knowing what people secretly want is a major theme of the episode.
He did it with Cho, Wiley, Abbot and Agent Fischer. He did the same with Marsha.
He figured out that she was secretly in love with Alex and hence would sacrifice herself to save him.

It fits very well with a theory i have been pondering fore some time now.

"Red John" is dead because it became irrelevant. Jane is no longer struggling against his true nature of being a sociopath, a killer and possibly a real psychic. Ever since the new beginning Jane ceased cynically arguing against any possibility of the supernatural.

He defeated McAllister by pulling a pigeon out of his jacket. There is not much else more classical and cliche when it comes to stage magic then to have live bird appear out of nowhere.