Sasha Alexander, Colin Egglesfield, Angie Harmon

How do you think hardened Detective Jane Rizzoli (Angie Harmon) will feel when her screw-up of a brother, Tommy (Melrose Place's Colin Egglesfield), begins to court her best friend, Dr. Maura Isles (Sasha Alexander)?

That question will be raised when Egglesfield makes his return to TNT's Rizzoli & Isles (10/9c, Monday). "He starts to have a little thing with Maura Isles because he's living in her house," Egglesfield tells TVGuide.com. "They start playing some chess games together and, kind of like The Thomas Crown Affair, there's a little sexual chemistry that starts to develop between the two of them."

Watch full episodes of Rizzoli & Isles in our Online Video Guide

Clearly, Jane will be displeased that Tommy, who recently finished a prison term, will be trying to corrupt Maura -- at least that's how Jane sees it. "She's definitely someone who's not happy with this because she knows Tommy and she knows how unpredictable he can be," he says. "So, not only is Jane apprehensive of letting Maura get involved with Tommy for that reason, because it's her best friend, but Tommy's the kind of guy who likes to push people's buttons and he's pushing Jane's."

While the rest of the Rizzoli family knows what a misfit Tommy is, Maura offers him a fresh start. "When Tommy's with her, she is a sense of groundedness that he lacks in his life," he says. "At the same time, I think Tommy is exciting for Maura because he's a little dangerous."

TNT renews Rizzoli & Isles for Season 3

Still, Egglesfield is quick to defend Tommy, who he says isn't necessarily the bad guy the Rizzoli family has made him out to be. "The longer he's around, the more you start to see that he's a good guy and that we want to trust him, but at the same time, he's not someone you instinctively would trust because of his past history."

Hmmm. Maybe he'll prove to be a proper suitor for Maura. Who doesn't want to see more of the Melrose Place alum around?

Rizzoli & Isles airs Mondays at 10/9c on TNT.