LOS ANGELES (KABC) -- A 16-year-old Bellflower boy was charged with one count of murder Friday in the fatal shooting of Downey police Officer Ricardo Galvez, the Los Angeles District Attorney's Office announced.The teen, Abel Diaz, was in court Friday afternoon at the Los Angeles County Superior Court.Galvez, 29, was killed Wednesday night in a botched robbery attempt , according to Los Angeles County sheriff's Lt. John Corina. The Whittier resident was found dead inside his own car at the end of his shift in the police department parking lot.Corina said at least two suspects walked up to Galvez's car and opened fire. Authorities said the suspects were not aware Galvez was an officer because he was in plain clothes.Diaz, along with 18-year-old Steven Knott and 21-year-old Jeremy Anthony Alvarez, were arrested and booked on murder charges early Thursday morning.Outside the courtroom Diaz's sister was seen distraught and shouted, "My brother is innocent, he is innocent...Steven is the shooter...he's a gang member."If convicted, Diaz faces up to life in state prison.The case remains under investigation by the Los Angeles County Sheriff's Department.Diaz's arraignment is scheduled for Monday afternoon. Prosecutors will ask for his bail to be set at $1 million.Knott and Anthony are being held without bail. Both are due to appear in court Monday.Meanwhile, the outpouring of support for the fallen officer, who was a former student at Bell Gardens High School, continued."Our school community sends our condolences to the family of Ricky, and we are saddened by his loss," said Juan Herrera, principal of the school.The Downey Police Department and the Downey Federal Credit Union set up a memorial fund to assist Galvez's family.Donations can be directed to Downey Police Cpl. Mike Pope, president of Downey Police Officer's Association, or to the Downey Federal Credit Union.Mike Pope - President of DPOA10911 Brookshire AvenueDowney, CA 90241562-904-2308mpope@downeyca.orgDowney Federal Credit UnionOfficer Ricardo Galvez Fund8237 Third StreetDowney, CA 90241562-862-8141Monday - Friday: 9:00am - 5:30pm.Saturday: 9:00am - 2:00pmNon-Business Hours Drop Off (Box is located by the ATM)Only cash or checks are being accepted at this time. Please make checks payable to "Officer Ricardo Galvez Fund."