Knoll was a CTU Los Angeles agent active during Day 2. After agreeing to go undercover with Joseph Wald's crew, Jack Bauer insisted that either Agent Knoll or Grothy go pick up his daughter Kim and get her out of Los Angeles, in case Second Wave's nuclear attack was successful. ("Day 2: 8:00am-9:00am") Wald's group bombed CTU Los Angeles a few hours later, killing thirty CTU personnel. It is unknown whether Knoll was among them. ("11:00am-12:00pm")