Twenty-one-year-old Anthony Alex Castillo and 19-year-old Robert Alex Lopez admitted that the shooting was done as part of street gang activity, according to the D.A.'s office.
Murder charges against Castillo and Lopez were dismissed as a result of their pleas. A Superior Court judge in Pomona immediately sentenced both to 21 years in state prison.
The investigation into Whitehead's killing led sheriff's investigators to an unrelated alleged conspiracy-to-commit murder plot, resulting in grand jury indictments against 11 people.
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