Anthony Valdez was Chief of the San Fernando Police Department as of 2016 when Harry Bosch began working as an unpaid volunteer. Valdez has lived in San Fernando his entire life and has been with the department for 25 years, in addition to putting in twenty years with the LAPD. Early in his career he investigated the disappearance of Esme Tavares. He believed she had been murdered by her husband, but there was never any evidence to arrest him. The case remained open for 15 years.
During his time in the LAPD, one of Valdez's early assignments was in a gang-suppresion unit in the Hollywood Division, where he ran afoul of Harvey Pounds and became the subject of an unsuccesful internal complaint filed by the lieutenant. It was during this assignment that Valdez first learned about Bosch after he himself got into an altercation with Pounds and threw him through the plate-glass window.
In 2017, upon learning that Tavares was alive after Bosch has located her, Valdez was furious and wanted to charge her with fraud. Bosch talked him out of it.