Captain Bell is Sergeant Walker and Sergeant Patrick O' Neil's commanding officer that appears in Call of Duty: Modern Warfare: Mobilized. He, along with O' Neil and Walker were the most prominent members of the "Gopher Squad".
After Patrick O' Neil got out of training, Bell, O' Neil, and Walker were sent to Venzuala to capture and interrorgate Colonel Ayala, the maker of a warhead that would be sold to Prince Farhad. They fought through a train station only to find out Ayala was already dead, so they hacked a nearby computer, leading them to a snowy weapons factory in the north. They destroyed the factory and were sent to a forest to stop the warhead from being transported, but ultimately failed as Farhad's men recovered it. So, they headed out to find the nuke by recovering the informant known as Al-Baq and help extract him out of the city.
Bell and his men were ordered to secure a power plant containing Farhad's warhead with the American AC-130s covering them overhead. They managed to fight their way through the infantry, ending with O' Neil disarming the nuke and saving all of Russia.