"Olive Oil" was a Mexican mechanic travelling to the U.S.
Olive Oil frequented the same passage from Mexico to Texas multiple times, and was a mechanic by trade. He mentioned having painted cars for some of the biggest gangsters in Michocacán, and that's how he got his nickname. He also had a cousin who owned an auto repair shop, and that his cousin had landed him a job painting cars ("No Más").
Olive Oil rode in the back of a truck along with 11 other passengers, including Marco and Leonel Salamanca. He tried to start a conversation with the two, first by telling them that they had officially crossed into Texas, and then by mentioning his upcoming job painting cars at his cousin's shop. However, the Cousins were unimpressed and merely didn't reply. Olive Oil then looked down and saw the Cousins' boots, which he immediately recognized as them being affiliated with the Juárez Cartel. He quickly became quiet and sat back, but the Cousins both looked at each other, knowing that Olive Oil was a risk, and shot him along with the other 9 passengers and the driver. Marco then set the truck on fire, further burning Olive Oil's body along with the others ("No Más").
The crime scene was later found by the authorities, and a photo of the passengers' charred bodies, Olive Oil included, was shown on a TV screen during a DEA meeting presided over by Hank Schrader ("Caballo Sin Nombre").