Be warned, CBS viewers: if you think Patrick Jane hit rock bottom on this week's The Mentalist Season 4 finale, creator Bruno Heller has some disturbing news.

"We’re certainly going to see a little more of that hard darker side of him," Heller previews to Entertainment Weekly. "That’s one of Simon Baker’s great assets as an actor, he can play both charming and dark at the same time. The show is not going to turn into a much darker show, but that character will show more of those colors. We’re getting closer to the meat of what the show is about."

As for Red John? Heller says it's conceivable fans have already met him, and is also prepared to disappoint many followers once the reveal is actually made.

"The trick is going to be - and this is coming - bringing the audience along and making them second guess themselves and ask, 'Is that him? Is that him?' Red John ultimately is just a man - whenever you see the great criminals reduced to the flesh it’s sort of disappointing. I have two seasons or so to make it come true. I can guarantee that people will be disappointed."

Visit EW to read the complete interview with Heller and the grade the fourth season of The Mentalist below: