'The Mentalist' Season 6 Episode 5 Spoilers: A Red John Suspect Returns [Video]

On this Sunday's installment of "The Mentalist," the hunt for Red John heated up as another Red John suspect was brutally eliminated from the list.

In the episode "Red Listed," someone steals Patrick Jane's (Simon Baker) fake list of Red John suspects, which was made to throw people off the search. After the list is stolen, the fake Red John suspects start to turn up dead.

The episode begins with one of those individuals on the list, Benjamin Marx, being found dead under a bridge. (Marx was buried alive by Jane to get Marx to confess to murder back in season four.) FBI Agent Reede Smith, who is one of the seven remaining Red John suspects, thinks Jane murdered Marx.

Patrick began to suspect that someone high up in the police rankings could be behind the murder.

The team goes out to warn the others on the fake list that they may be in peril, but they are too late for one unlucky "suspect"; Richard Haibach is captured and tortured.

It is revealed that Bob Kirkland captured Richard, which allows Jane to figure out where Richard is being held. Kirkland turns it around on Jane, and tries to get information out of him about the real list of Red John suspects. Then comes another revelation: Kirkland's brother was killed by Red John, so he's also on a personal mission to track him down, much like Jane. Lisbon (Robin Tunney) arrives just in time to save Jane from Kirkland's clutches, and Kirkland is taken into custody.

At episode's end, Kirkland is put into the back of a police van and stripped, then he is taken out by a police officer and told to run. The officer then shoots and kills Kirkland, eliminating another name from the list of Red John suspects.

The latest episodes of "The Mentalist" have a noticeably darker tone, which is intentional, said series writer Rebecca Cutter.

"I really enjoy writing the humor; I love writing Jane's dialogue," Cutter told The Inquisitr. "This whole season has been a little gorier than normal. There are other shows out there where cutting off fingers is no big deal; that's like nothing. But on our show, that's darker than we usually go."

The clues that fans learned in this past episode will come to light later on in the season.

"That all will come to bear a lot, coming down into the final episode, when we reveal who Red John is," Cutter said. "All of that will blow up and be explored very thoroughly and have bigger implications for CBI."

In the next episode, "Red Tattoo," Red John suspect Ray Haffner will return to assist on a case.

The synopsis reads, "When a prominent member of Visualize is mysteriously killed, Jane investigates in the hopes that the case will provide a clue that will lead him to Red John."

Watch the promo for "Red Tattoo," which airs Sunday at 10 p.m. on CBS.