Robin Tunney, <I>The Mentalist</i> Robin Tunney, The Mentalist

Nearly every show on TV has to deal with will-they-won't-they sexual tension between its series leads. CBS' The Mentalist is no different.

"You always want to keep the audience wanting and guessing," Robin Tunney tells "Once it happens it's very difficult to know where to go from there."

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As California Bureau of Investigation Agent Teresa Lisbon, Tunney finds herself fighting that battle with co-star Simon Baker

's Patrick Jane. Lisbon's disdain for Jane slowly gave way to flirty camaraderie, and in the Season 1 finale, Jane fatally shot a man to protect her. But that doesn't mean 'shippers should expect a wild love affair in Season 2."They're closer," Tunney says. "I think their exchanges have become a lot more honest. Does that lead to romance? I suppose sometimes. But I can guarantee the readers that there is no making out in the first nine episodes. But they are closer, and I think she's grateful to have him around."However, that closeness turns Lisbon's unit upside down when the CBI takes the Red John case away from her. Naturally, Jane — whose wife and family were murdered by the crimson serial — doesn't take the news very well."I stop being his boss, and we lose the case because of it," Tunney says. "I let him get away with too much and put him on a longer leash because I'm grateful. It's a profound loss for both of us. For him it's an emotional thing, and he can't let it go, and he goes to great lengths — illegal lengths — to stay on it."

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Now leading up the Red John investigation is Sam Bosco (Oz's Terry Kinney), a by-the-book cop isn't at all charmed by Jane. And as luck would have it, Bosco has a both a professional and romantic background with Lisbon."Bosco is kind of in love with Lisbon," Tunney says. "That brings up Patrick's feelings about me, which is like a little bit of a triangle, and it's fun. It's nice to be fought over, but it's very subtle. There's a lot of looks, and Patrick is a little jealous, just as Bosco is jealous of the attention that Patrick gets from Lisbon. The closeness that we have is infuriating to him."Lisbon and Bosco also share more than a history between the sheets. "There's something that happened in their past that could destroy both their careers if the lid's blown off of it," Tunney says. "It's something my character could potentially use as leverage against him and alternatively he could use as leverage against me. It's very slowly revealed."Tunney says she's excited for the second season and the opportunity to learn more about all the show's characters. She says this season will provide more insight into her troubled upbringing and the trauma it caused. It's not all doom and gloom, though: The blossoming romance between Rigsby (Owain Yeoman) and Van Pelt (Amanda Righetti) will get a boost.

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Tunney also says viewers will see a slightly grittier show this season, thanks to The Mentalist's new 10/9c timeslot. She notes in particular that the details of Red John's murders will be more graphic, which will no doubt only increase Jane's fervor for catching him.But like the Lisbon-Jane romance, that's probably going to have to wait as well. "The reason [Jane's] working with us is to catch [Red John], so I think if we caught him, Jane's objective for being there would be gone," Tunney says. "He's not helping us out because he wants to fight crime, he's doing it because he needs a sense of revenge. So I think it will be a long time coming. Selfishly, I would like to because it would mean my character is a better cop, but I don't think it's going to happen."The Mentalist returns Thursday at 10/9c on CBS.