Colonial Intelligence (a.k.a. Colintel or ColIntel) is a military intelligence division of the Colonial Fleet.
Agent Christa Nolan of Colintel selects seven Viper pilots, including Kara Thrace and Karl Agathon for a mission to prevent Darja Purat from falling into terrorist hands, while escorting him through the Virgon moon cluster.
However, it appears that Purat himself has his influence over one or more people in Colintel, as he was able to recruit Nolan, who helped him escape from his prison transport ship (Battlestar Galactica: Season Zero 3).
After the incident, Agent Levin from Colonial Intelligence arrives on Galactica in order to take charge of the mission to pursue Purat. As it is within his authority to take command of the battlestar, Levin does so after it becomes apparent that Commander William Adama and Colonel Saul Tigh refuse to deploy nuclear weapons in order to take out Purat (Battlestar Galactica: Season Zero 4).
Colonial Intelligence is also responsible for ensuring the security of sensitive data. As the Cylons make their final attack on the Colonies, Anna Bazinet recruits Owen Wilkens' prisoners on the Astral Queen to remove servers from the Gemenon Data Processing Complex, so as to prevent them from falling into Cylon hands (Battlestar Galactica: Zarek 4).