By Dan Whitcomb
LOS ANGELES (Reuters) - Two more suspects were charged with murder on Monday in the fatal shooting of a police officer as he sat in a car outside his department's headquarters in the Los Angeles suburb of Downey, prosecutors said.
Steven Knott, 21, and Jeremy Anthony Alvarez, 18, were each charged with one count of first-degree murder, along with special circumstance allegations that make them eligible for the death penalty if convicted, the Los Angeles County District Attorney's Office said in a statement.
Abel Diaz, 16, was charged on Friday with the murder of Downey police officer Ricardo "Ricky" Galvez but does not face the death penalty because he is a minor.
A source close to the case has previously said that Diaz was not believed to have been the gunman but still faces murder charges because he is accused of taking part in the attempted robbery that led to the officer's death.
All three defendants, who are also accused of belonging to a street gang, were expected to make court appearances later on Monday afternoon.
Galvez, 29, was sitting in his personal car outside the Downey Police Department on Wednesday night when the three suspects ran up to the vehicle and opened fire on the former U.S. Marine in the community 10 miles (16 km) southeast of downtown Los Angeles, according to the Los Angeles County Sheriff's Department.
A fellow officer driving nearby heard the gunshots, saw a vehicle leaving the parking lot and gave chase, ultimately seeing the occupants of that vehicle ditch it in a residential area of neighboring Montebello before fleeing on foot, Sheriff's Lieutenant John Corina said at a news conference earlier this week.
Knott, Alvarez and Diaz were arrested during a search of the area, and police recovered a revolver believed to have been used in the shooting of Galvez.
Diaz's 24-year-old sister, Maricela Alvarado, told reporters outside court on Friday that her brother was not responsible for the death of Galvez, the Los Angeles Times reported.
Alvarado said her brother had told her on the night of the crime that his friend had shot the officer, according to the Times.
(Reporting by Dan Whitcomb; Editing by Lisa Shumaker)