Theo was 22, and the quartermaster, caring for all the equipment and carrying additional ammunition that might be needed during a mission. On a probationary contract pending Reilly's decision, Theo recently succumbed to super mutantordnance somewhere within the sprawling Statesman Hotel, near where the remaining team is holed up.
Theo's corpse can be found in a stairwell in the Statesman Hotel. His ammunition box can be looted (during the quest) if Reilly gives the player the code (Reilly9090). Inside are 200 5mm rounds, 100 5.56mm rounds, 100 10mm rounds, and 4 frag grenades. If the ammunition is taken from the cache, the player can either keep it or share it with the other members of Reilly's Rangers on the roof of the Statesman Hotel.