Treat Williams Guests, Paul Guilfoyle Exits in the CSI Season Finale

Two small-town murders, connected yet separated by a quarter of a century, will bring Treat Williams to CSI: Crime Scene Investigationfor a guest stint on Wednesday's season finale, "Dead in His Tracks." (10/9c on CBS). The former Everwood star plays security guard Sam Bishop, who was an investigator on the first murder back in 1989 but retired from cop work in frustration when he couldn't solve the case. Now Bishop has reappeared and D.B. Russell (Ted Danson) is leery of him — but suspicion soon turns to awe.

"It turns out Bishop was a man way ahead of his time — a proto-CSI," says Andrew Dettmann, who wrote the episode. "So much of our modern CSI work uses technology that wasn't available in Bishop's day, yet he was using his own inventions to solve crime — like a homemade recipe for detecting gunshot residue and a jerry-rigged camera and weather balloon that did aerial photography like the drones of today."

D.B. is hugely impressed by Bishop's pioneering methods and the men form a genuine bond. According to executive producer Don McGill, Williams' character might have recurring potential. "Treat certainly let it be known that he'd be up for it!" says McGill. "He and Ted are old friends and they had a great reunion on the set. They make a great team."

The episode also marks the farewell of crusty Captain Brass, played by Paul Guilfoyle, who has been written off the show. "We reached a place, creatively, where it was time to say goodbye to Brass, but that doesn't mean we won't want Paul to return in some capacity in the future," McGill says, noting that the season finale, "will revisit the relationship between Brass and his bad-seed daughter Ellie [Teal Redmann] and bring some closure to it."

The plot has Ellie attempting suicide but "it opens the door for reconciliation," McGill says. "There is a surprising resolution for the two characters. It's a chance for a new beginning."

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