LOS ANGELES -- We're learning more about the death of a 13-year-old Southern California boy who was allegedly murdered by his soccer coach. Oscar Omar Hernandez, of Los Angeles' Sun Valley neighborhood, died of acute alcohol poisoning, according to the Ventura County Medical Examiner's office. The teenager's body was found on the side of a road in Oxnard earlier this year. His family said he boarded a Metrolink train to the Lancaster area to help a soccer coach at a complex there. When he didn't return home that night, the family worried and started looking for him. They reported him missing. His body was later found in Ventura County. The boy's accused killer, 43-year-old Mario Garcia Aquino, was charged with one count of murder with the special circumstance allegation of murder during the commission or attempted commission of lewd acts with a child. In May, our sister station, ABC7 Eyewitness News in Los Angeles, learned a backlog of cases at the district attorney's office may have led to Garcia Aquino being free rather than facing charges for two other alleged sexual assaults.