Xavier Martinez, 16

Xavier Martinez, a 16-year-old Latino, died Saturday, Dec. 20, after he was shot in the 12400 block of Washington Place in Mar Vista, according to Los Angeles County coroner’s records.

Shortly before 11:30 a.m. on Dec. 19, Martinez was standing outside of an apartment complex when a gunman walked up and opened fire, according to a news release from the Los Angeles Police Department.

Police set up a perimeter in the area but were unable to find the gunman. Witnesses were "uncooperative with investigators," Sgt. James Mankey told CBS-LA.

Martinez was taken to a hospital, where he was pronounced dead at 9:20 a.m., on Dec. 20, said Ed Winter, assistant chief of investigations for the coroner’s office.

Greg Steven Garcia, an 18-year-old Latino, was arrested on suspicion of murder 10 days later, according to online L.A. County Sheriff's Department records. Garcia has been charged with one count of murder, according to the Los Angeles County district attorney's office. He is due in court Jan. 28.

Anyone with information is asked to call West Bureau Homicide at (213) 382-9470. Those who wish to remain anonymous can call Crime Stoppers at (800) 222-8477.

-- Nicole Santa Cruz