Agent Dalton was in the field with Agent Baron and other agents during an operation to discover the whereabouts of Habib Marwan. While the terrorist Joseph Fayed drove Jack Bauer and Dina Araz (who worked undercover for CTU) to meet Marwan, they were tailed by Baron, Dalton, and other CTU agents with a listening device. Fayed unexpectedly stopped beneath a bridge, transferred his hostages to one of Marwan's henchmen, and was given a bomb. When Baron went to apprehend Fayed later, the bomb detonated, killing them both, and Dalton radioed in to report what happened. Tony Almeida promised to send him a backup team.
Background information and notes
The Region 2 DVD subtitles give this character's name as "Alden".