Two small-town murders, connected yet separated by a quarter of a century, will bring Treat Williams to CSI: Crime Scene Investigation for 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."