|Affiliation:||Counter Terrorist Unit|
|Profession:||Intelligence agent, CTU Los Angeles|
|Appears in:||Chaos Theory|
Seth Ludonowski was an intelligence agent at CTU Los Angeles before Day 1. Energetic and resourceful, Seth was a valued member of CTU's data analyst corps, although both Jamey Farrell and Tony Almeida suspected he would eventually tire of the job's unique demands.
On Jamey's recommendation, Tony brought Seth on board to assist his investigation into Jemaah Islamiyah, an Islamist terrorist group whom he suspected of targeting the Pacific Rim Forum being held in Los Angeles. Seth identified Riduan Bashir, a local businessman with ties to the group, and later confirmed for Tony that the man Tony had seen him meeting with was Encep Sungkar, JI's third-in-command. Seth assisted throughout the night as Tony went undercover to infiltrate an arms deal between the Indonesians and a local weapons fence in order to determine their plans.
The next morning, Seth attended a briefing by Nina Myers, who had learned that the fugitive Jack Bauer had been working with Ryan Chappelle to capture a notorious international terrorist named Zapata. On hearing Zapata's birth name, Jorge Rafael Marquez, Seth started, and said that Marquez was famous for his innovations in computer algorithms. Half of CTU's systems ran software built on his ideas. When Jack returned to CTU, Seth and the other analysts set to work determining how Zapata was connected to Jemaah Islamiyah and where his planned attack would take place. Although the evidence suggested that JI would be targeting the Pacific Rim Forum, Seth remained unconvinced by intelligence he found, telling Jamey that it appeared Zapata had first reached out to the Indonesians, rather than vice versa.
In the afternoon, after Jack returned to CTU without any leads, Seth timidly asked if he could leave for the day, saying that he had tickets for the Harmon vs. Silva fight at the Staples Center. Jack angrily refused, but then was startled upon hearing the name of the championship: Professional Reality Fighting, which had the same initials as a code-phrase used by Jemaah Islamiyah before the crisis. Thanks to Seth's request, CTU determined that Zapata's plan was to assassinate Fed Chairman Martin Webb as he attended the fights. (Chaos Theory)