Marg Helgenberger, CSI

CSI's 10th season has seen Catherine Willows (Marg Helgenberger) rise to the challenge of being a supervisor. But how will she respond when one of her team members is suspected of murder?

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In Thursday's episode, Dr. Ray Langston (Laurence Fishburne) continues his obsessive hunt for serial killer Dr. Jekyll. But when Heidi Custer (Monet Mazur), an investigative reporter from Langston's past, ends up dead, some begin to wonder if Langston himself is behind the Jekyll murders.

"There are some doubts in some of the other team members, but Catherine is the one who really has his back," Helgenberger says. "As a supervisor, it's important to really give everyone the benefit of the doubt and remain as objective as you possibly can. I think Catherine is a very inclusive leader, and being a woman, I think she's a little more aware of and sensitive to the team's feelings and thoughts. But she's also getting more and more confident and she'll do what she needs to do."

Even so, Catherine takes Langston off the case because of his suspicious behavior. Fortunately, other team members rally around Ray. "Langston can't be on the case, but Nick is his eyes and ears," executive producer Carol Mendelsohn tells us. "Together, they investigate the death of Heidi Custer, assuming that while she was following Langston, she crossed paths with Dr. Jekyll and that she is another victim or collateral damage."

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The biggest break in the Jekyll case, however, comes when Nate Haskell (Bill Irwin), aka the Dick and Jane Killer, reaches out to Langston to help identify Dr. Jekyll. Haskell's offer makes for a very tricky situation for Catherine, who agrees to allow Haskell to be transferred to Las Vegas to help in the season finale.

"Catherine really puts her job on the line by going above Captain Brass [Paul Guilfoyle] to make this happen," Helgenberger says. "We don't have any other leads or any other choice. She'll do whatever it takes, and she sticks to her guns. She doesn't care about hurt feelings of Brass' puffed-out chest. It's a risk she has to take."

But what if Brass is right? "I don't think Nate Haskell ever does anything that's not planned out. Everything with him is calculated and part of a grand design," Mendelsohn says. "Brass has a very bad feeling about bringing Haskell to Vegas, because the last time they gave this guy a stage, somebody got killed. Brass is reluctantly dragged into this, but his cop sense says it's going to end up in a bad way."

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Even with Haskell's help, Helgenberger says stopping Dr. Jekyll will require all the CSIs to collaborate. "I think our show is at its best when everything centers around one crime," she says. "The whole team rallies together, and it's always great to see how the team operates with each other. The finale is actually one of our better finales. It's very suspenseful and filled with action. It does a lot of zig-zagging."

And, of course, a few of the team members find themselves in dangerous territory, Mendelsohn says: "One or more of our CSIs will fall victim to one or more of our serial killers."

Who do you think will end up in danger?