Under the callsign of "Deadly," Cpt. Pelayo provided close air support for USMC 1st Force Recon during the raid to capture Khaled Al-Asad . As she was escorting helicopter unit Outlaw 2-5, a nuclear device was confirmed to be in the city and shortly after she was shot down by a stinger missile. Outlaw 2-5 made the decision to land and attempt a rescue despite the imminent nuclear threat. Lt. Vasquez and his unit managed to get to her before enemy forces could overwhelm the crash site. Sgt. Jackson carried her back to Outlaw 2-5, and moments later the nuclear device was detonated. The initial blast and ensuing fallout resulted in the death of everyone on-board Outlaw 2-5.
It's interesting to note that Pelayo is the only female soldier portrayed in Call of Duty 4. She also has the distinction of having the highest rank of any soldier shown in the field. Her model was based on Infinity Ward employee Velinda Pelayo, and she was voiced by Anna Graves.
There is a possible reference to Cpt. Pelayo in Modern Warfare 2. In the Favela multiplayer map, there is a store called Pelayo's.