Oscar had been living with his mom and dad in Los Angeles, during the time his father Ramon was working as a security guard for the Port of L.A. after his time as a Navy SEAL.
In their time together, Oscar and his dad would play catch together. Little did Ramon know, his father secretly had stolen heroin from his superior at the port and they were all going to start a new life in Arizona. Now, he became so disturbed in that his father had died in a supposed suicide, which, however, to Riggs and Murtaugh seemed unlikely.
Apparently, Oscar's father Ramon had stolen heroin from a drug dealer, Levon Tibibian, and his wife, Mrs. Alvarez, kept it well hidden, and Ramon was killed for it. Oscar, however, was kidnapped, in order to get the heroin back in exchange for Oscar to be released to Mrs. Alvarez. Riggs goes in to save Oscar, and Murtaugh soon after joined in and they killed the bad guys, including Tibibian and Hennicky, and rescued Oscar.